Last week, Amazon announced a new voluntary service that allows its own contracted delivery personnel to temporarily access customers' homes through a new service dubbed "Amazon Key," which begins Wednesday, November 8.

Privacy experts have wondered what putting such a camera in the home could mean for law enforcement, particularly given last year's episode when Amazon refused to help law enforcement in a murder case in Arkansas. There, investigators attempted to get the company to hand over data collected by a nearby Alexa. If that instance is any indication, Amazon may resist a legal demand to open up an Amazon Key lock.

Beyond concerns about the police, many on Twitter are fundamentally uncomfortable with Amazon Key.

I'm excited to watch the 2030 Netflix docudrama about the Amazon Key murders — Larissa Barrett (@larlibarrett) October 25, 2017

*Calls Customer Service* Hi. I used the Amazon Key service and now my Xbox is missing. Also, they let my cat out. I’d like to cancel. — Kevin Plantz (@KevinPlantz) October 25, 2017

Several lawyers have also wondered what kind of legal questions Amazon Key now poses.

"Would it be possible for a person unknowingly to authorize a law enforcement agency or a criminal to access Amazon Key?" Elizabeth Joh, a law professor at the University of California, Davis, e-mailed Ars. "If a criminal gains access and some harm occurs, who is responsible? And what criminal law would apply? Also, does Amazon have in its disclaimers that law enforcement might ask for access through Amazon Key? Does Amazon plan on being transparent about this?"

Ars put these questions to Amazon, which declined to answer them on the record.

"Why would anyone want to give Amazon access to their home?" said Brian Owsley, a law professor at the University of North Texas and a former federal magistrate judge. "This is like giving Apple your fingerprints or facial features. Have packages sent to your office or buy small post office box for much less than the cost of this service, and have packages sent there. This is just a very bad idea. How long before hackers can gain access to your home just like they gained access to vehicles with computer systems?"

Plus, it's not clear what legal standard would apply if law enforcement wanted to get at the footage. Would such a recording require a warrant? Would it be subject to the third-party doctrine? That's the legal notion that data handed over to a third-party (here, Amazon) cannot be considered private, so the government can access it without a warrant.

"It is doubtful that law enforcement could obtain video footage, especially if it contains audio without a warrant," Christopher Slobogin, a law professor at Vanderbilt University, e-mailed Ars.

"However, law enforcement would likely argue that the homeowner has no reasonable expectation of privacy in that video based on the third-party doctrine. For example, the Supreme Court in Smith v. Maryland determined that the third-party doctrine barred the telephone subscriber from claiming a reasonable expectation in privacy of the numbers that he dialed. Similarly, courts have concluded the same thing about a customer's electricity usage that the electric company maintains in its records."

Happiness is a warm lock?

The $250 setup includes a Bluetooth-enabled smart lock and a new Cloud Cam security setup. According to an Amazon spokesperson, contracted drivers will be granted "one-time access" following the verification process through a handheld mobile device. Such access can be blocked or revoked at any time.

According to Amazon, the camera is motion-activated (video and audio, including a speaker) and only captures when an in-home delivery is about to take place.

"[This procedure ensures] the right driver and package is at the correct address and that the driver is near the door," the spokesperson told Ars. "Second, we use Amazon Cloud Cam to record deliveries so customers can review a video clip of the delivery. Third, drivers will not move onto their next delivery until the door has been securely locked."

Like all of its other products, Amazon Key has its own "Terms of Use," which provide a guide for the company’s thinking. If you use the service, you automatically agree to these terms, which can change at any time. (At present, these terms make no reference to law enforcement.)

Amazon says it will correct any errors or damage through its "Happiness Guarantee." If that's not enough and you want to sue, Amazon says you can't sue in regular court: you have to take the case to private arbitration, a process that generally favors companies over individuals.

As the Terms state:

If you place an order with in-home delivery, you are authorizing Amazon and its delivery providers to access the home (or other location) that you designate as the order shipping address, for the purpose of delivering your order. By placing an order with in-home delivery, you are confirming that you have the right to authorize Amazon and its delivery providers to access the designated home. … Amazon has no responsibility or liability for the following: third party accounts or services; Compatible Products that Amazon does not manufacture or develop; any guests or service providers to whom you provide authorization to operate your lock.

According to law professor Ryan Calo of the University of Washington, Amazon is carving out what it is and isn't responsible for.

"Amazon and its delivery providers get access to your home," he told Ars. "So, if Amazon or its delivery providers leave your door open, Amazon can be liable. But if you use Amazon's app to open the door for other providers, that's on you (and them)."

Put another way, in a purely analog world, it's your own fault if you leave a key under the mat and the person you trust with it abuses that trust. With new tech entering the picture, Amazon is seemingly only responsible for package delivery.

For what it's worth, neither FedEx nor UPS indicated that they would be offering a similar service any time soon.

"As policy, we do not comment on competitors' business plans," FedEx spokeswoman Gretchen Mathis told Ars in a statement. "FedEx is committed to offering our customers secure and convenient delivery options."

Similarly, UPS spokeswoman Dawn Wotapka told Ars that UPS drivers "do not enter or otherwise leave packages inside homes."

"We do evaluate new technologies and opportunities to meet our customers' needs," she said. "Our employees have a time-tested method of delivering packages that has proven for more than a century to work. However, we're always willing to listen to new ideas. While there's nothing that precludes us from doing this, one of the biggest questions about this service will be user acceptance. We're watching to see if consumer demand grows to a point where it makes sense."