For a gadget we've been hearing about for months, Google Home still packs an awful lot of mystery.

It's no wonder: There are just so many things we can't know about a voice-controlled tabletop assistant based solely on marketing descriptions and closely controlled demos. How well will the device actually work in a normal and noisy household environment? What will it be like to interact with the Google Assistant without being able to see anything on a screen (especially when the software returns web results as an answer)? And how will the gadget handle incoming commands from multiple people with multiple Google accounts?

We'll have to wait until Google Home hits store shelves later this week for many such answers. But the last question -- perhaps the most common and pressing one I've heard asked about Home over these past several months -- is something we can address right now.

And the answer, I'm afraid, isn't something most people are going to like.

Google Home's account conundrum

I've been among those wondering about Google Home's handling of multiple users -- because as I try to wrap my head around what Home can do for my family that's different from what our phones already do, the main answer I keep coming back to is that it could make it easier for anyone in our house to complete "intelligent" tasks without having a phone nearby.

That could be particularly useful for visitors who might want to cast videos to the TV via Chromecast, for instance, or play music via our various Chromecast Audio-connected speakers. It could make it easy for anyone to control the ambiance-adding Hue lights around our living room. And it could be valuable in the future as our now 20-month-old daughter gets older and starts wanting to interact with the internet without having a dedicated device of her own.

Here's the problem, though: As the person who sets up the Google Home device, everything that happens through that device will be tied to your Google account -- no matter who's doing the talking. And when you think about that in practical terms, there are plenty of situations in which it could be less than ideal.

Part of what makes Google Home appealing, after all, is its tight integration with Google and the numerous Google services so many of us rely on. Much of Google's new hardware push revolves around the idea of having a single personalized assistant that knows you, learns from you, and responds to you -- regardless of where you are or what device you're using. But with Home, that personalized assistant is effectively opened up to anyone in your house.

That means commands like sending or reading out emails, setting and reviewing reminders and events, and accessing or adding to lists will always revolve around your personal Google account -- even when you aren't the one talking to the Home device.

Beyond that, any YouTube videos played via voice command will be connected to your account and will affect your future YouTube recommendations. And any searches or general questions asked of Home will go into your personal search history and then affect things like how the Google Assistant interacts with you in the future and what cards appear in your smartphone's Google app feed (which is influenced by your personal search history).

So wait -- all of this is actually for sure?

Yup -- according to Google. I dug around and found a new Google help document that uncategorically confirms Home's single account nature and lays out the realities of that in plain and simple terms.

Here are the key points, with Google's own wording in bold:

"Today, Google Home only supports a single account on the device -- but you can use multiple accounts with your music services."

So there is that one exception. But for everything else -- the core areas that are the most personal and impactful -- it's one account per Home device.

"A really useful assistant takes your context into account, and Google Home is designed to use prior queries to help answer later ones."

No "guest mode" or "incognito mode"; everything said to Home becomes a part of the associated Google account and affects how things work in the future. The only way around that is if you want to retroactively go into your Google account settings, find your Assistant history, and delete specific queries on a case-by-case basis.

"You can control the permission for Google Home to access your personal information like your calendar and Gmail device-by-device from your Google Home app."

That means if you don't want your Home device to be able to access your Google Calendar or Gmail data, you can block its access to those areas completely. But each area is an all-or-nothing switch; if you turn off such access for the device, it won't be there for you, either -- and that meaningfully reduces the value of having a Google-integrated product in the first place (the whole "universal personal assistant" thing -- remember?).

You could always toggle certain areas of access on or off occasionally, of course, depending on the situation -- but that's one more thing to remember to do (and after a couple of months, are you really going to bother?).

"Currently, we don’t have an ability to differentiate users by different voice patterns."

Now, that's what would have been spectacular -- "magical," one might even say! -- though it obviously does present some practical challenges. Maybe in a future generation?

"If someone is in the room, they have access to your Google Home. ... You shouldn’t leave your Google Home where people you don’t trust can access it if you have given Google Home access to information you consider confidential."

So, again, you can choose between substantially limiting what your Google Home device is able to do or effectively opening up your account to anyone who happens to be around.

It's a multiperson gadget that revolves around a single person's data

Given that Google Home would presumably be in, you know, your home, the risk is probably low for any sort of malicious "hacking" (though take a moment to imagine how fun it'd be to mess with a friend if you had 30 seconds alone with his Home device). More likely, we're talking about inadvertent effects and limitations -- a kid playing around, a visitor or babysitter trying out commands without realizing the implications, or a spouse or significant other having access only to your account for many of Home's functions.

And that, I think, is the root of the problem here: the fact that Google Home is taking a highly personalized assistant and putting it into a device designed to be used by multiple people. It's essentially a multiperson gadget that revolves around a single person's data.

To be fair, Amazon's Echo -- Home's primary competitor in the tabletop assistant space -- isn't great in this regard, either. (The Echo does allow for multiple user profiles, but those are mostly just for sharing Amazon-purchased content from multiple Amazon accounts.) The difference, however, is that Amazon doesn't have the ecosystem of data and services that Google does. What's connected to your Amazon account is far less inherently and intimately connected to your life than the scope of things associated with your Google account.

In other words, all of the qualities that give Google Home a leg up on the Echo -- the various forms of integration with so many Google services and so much personalized Google knowledge -- are the same qualities that could also make it more problematic in practice.

Home, sweet Home

Is all of this to say you shouldn't buy Google Home? Not at all. This is still a very new category of device, and there's certainly more to the picture than this one factor -- however significant it may be. And even that significance is very much relative; depending on the specifics of your household and your overall situation, all of this may or may not be a big deal or anything you'll actually ever worry about.

With Home set to go on sale this Friday, we're bound to see in-depth reviews starting to show up everywhere before long. You'll want to consider those and the full scope of what Home is actually like to use before making any decisions about whether it's right for you.

But you'll also want to keep this caveat in mind -- because by venturing into uncharted waters with Home, Google is opening the door to unprecedented complications. And whether you're simply considering Google Home or already planning to use it, you should be fully aware of all the ways it'll fit into your life.

[UPDATE: In the discussion of this story on Google+, Yonatan Zunger -- the head of infrastructure for Google's Assistant team -- confirmed that this is considered a "known issue." He said that while he can't talk about specific plans or timelines, his team is "definitely aware" of it and "want[s] to resolve it stat."]