Totally true. Though the reason why isn’t what many think
This is something I personally have been taking part in for a few years now, though the drops are far and few in my general area. The concept started in New York City back in 2010. Aram Bartholl installed a USB storage device poking out the side of a wall. On the drive he left some interesting goodies.
The concept began to spread and for the most part, the content on the flash drives are safe. I’ve ran into various works of art, books and stories, mini games, home-made movies, occasionally some porn, and even a few encrypted files. Some of the encrypted files I was able to get open, others I was not so successful with. But every so often I find a map. Sometimes the map leads to cool hidden gems around the town, other times they lead to other drops, and – well there are a couple I’ve yet to figure out.
But yes, this is very much a thing. But for the most part it’s not a secret spy ring, not a bunch of hackers, it’s mostly individuals sharing content and having fun.
The idea that spies used this was once entertained, but it didn’t take long before that was debunked. Imagine you’re a spy and your contact put secret files on a USB device stuck in a wall. It wouldn’t take long before someone saw this, and likely this USB device would be watched by other spies and intelligent agencies. Because the USB device is affixed to the wall, you can’t take it with you. So instead you’re stuck there for anywhere from 30 seconds to a few minutes extracting the information. Not very ideal for a spy.
But yes, Dead Drops do exist. But before going out to search for these, I do advise you find yourself a great anti-virus and anti-malware program as well as a device you don’t mind possibly becoming infested with malware or potentially breaking the USB port due to the positioning of the device during the file transfer.
I personally use an old Android phone with USB adapter.