Also, in my anecdotal experience, the most common failure mode of an USB stick seems to be going completely dead without any prior warning. So regular backups, definitely.
I don't know... one of those things where you think too much about it... like what about general consumers with a password on their Windows/Mac computer... is that "secure"? I don't know.
You could potentially access that hard drive by taking it apart assuming it wasn't a soldered on storage device.