I had one that didn't spin down when I pressed the eject button on the drive. It briefly flew around the room like a Frisbee. It bounced off the wall and ended up on the floor. It didn't break but it was so scratched it became a coaster.
IMHO, flash drives a re a lot more reliable than optical disks. I've got 24 plus thumb drives kicking around and only ever had one die. I've had a few optical disks that were unreadable just because of a finger print or spot of dust. Scratch one and t all over for any data on it, and trust me, they are easy to scratch, even if your careful handling them. Dropping a thumb drive isn't going to hurt it. Unless its into a bucket of water or out of a window.