A photo that Facebook chief Mark Zuckerberg posted Tuesday has inadvertently sparked a welcome discussion about hardware security.

Meant to celebrate an Instagram milestone—the Facebook-owned photo-sharing app topped 500 million active users—the image’s background shows a desk with a laptop that sports a couple of non-standard features. As one Twitter user noticed and Gizmodo highlighted, the MacBook in question sports small pieces of tape over both its webcam and the audio input area. (“Wow, Mark Zuckerberg is Paranoid as Fuck,” read the Gizmodo headline.)

There’s some sweet irony in the apparent discovery that the founder and CEO of Facebook—a company famous for inhaling and capitalizing on its users’ personal data—guards his own computer so carefully. But Gizmodo’s conclusion requires a couple of jumps.

First, it isn’t entirely clear that the computer belongs to Zuckerberg, although Gizmodo provides some anecdotal evidence that it does.

Second, and more importantly, putting tape over your webcam cover is not really such a paranoid thing to do. My laptop has tape over its webcam as I type this. So does the laptop of my colleague Lily Hay Newman, who covers cybersecurity. Neither of us are in the habit of wearing tinfoil hats. But unlike alien mind control, webcam hacking is a demonstrably real phenomenon, so much so that the Atlantic once dubbed it an “epidemic.” It isn’t just criminal hackers and voyeurs who are breaking into people’s webcams. The Snowden leaks revealed that the NSA does it, too.

You and I are probably relatively unlikely to be targeted in such an attack, although you never know. Zuckerberg, in contrast, is highly likely to be the subject of various attempted hacks, to the point that it would be rash of him not to take extra security measures. FBI Director James Comey does it, too.

But even if you aren’t Zuckerberg or Comey, putting tape (or a cute cat sticker, as one of my editors does) over your webcam is a pretty simple step you can take to provide yourself a little peace of mind at very little cost. When you need to use the webcam, just move the tape or sticker an inch to the side. When you’re finished, put it back. As Tyler Lopez wrote in Slate in 2013: “You Should Never, Ever Leave Your Webcam Uncovered When You Aren’t Using It.”

The practical effect of webcam tape is not only to thwart would-be hackers, but to ensure that you aren’t unwittingly broadcasting yourself—for instance, by forgetting to close a videoconferencing app. And the psychological effect is to make you more aware of the sensors that could potentially be monitoring you in your own home, including smart speakers such as Amazon’s Echo. Both effects are salutary.

The value of that second piece of tape on the computer that might be Zuckerberg’s is a little less clear-cut. Some initially assumed it was covering the computer’s headphone jack, but as Fusion’s Kashmir Hill points out, all that would accomplish is to make it hard to plug your headphones in. More likely, it’s covering the tiny dual microphones built into the side of the machine. In an informal test, Hill found that would muffle the audio signal, but wouldn’t block it out.

When you think about it, the surprise here is not that Zuckerberg, or anyone else, would want to cover their webcam when it isn’t in use. It’s that he has to use a piece of tape to do it. As privacy expert Adam Harvey points out, in an era when we’re increasingly aware of all the threats to our personal security, it would make a lot of sense for Apple and other computer makers to simply build webcam covers into their machines.