The overwhelming majority of people who use USB sticks for things are likely aware of security and the concept of encryption. But the idea of being able to use “free software cryptography on top” may as well be a trip to Mars.

Most "normies" I know think that open source cryptography is less secure because it's "open" (if they even know open source cryptography is a thing at all). No amount of trying to explain to them how more eyes on the source code generally equals safer encryption will sway most of them in the slightest.