USB Stick Watcher is a reminding and error checking software for USB pen drives. It reminds you in frequent intervals (45 minutes to 3 hours, according to your settings) about the status of your USB pen drive, if your pen drive is still plugged in a computer. This is useful for people who transfer their data across different computers or using a public computer, as leaving it unplugged may pose a security risk especially when you are using public computers.

USB Stick Watcher also checks for disk errors. Moreover it will show a warning message every time when you try to turn off your computer, or log off without unplugging your pen drive. So that this program will ensure that you never leave your USB Stick plugged in to a computer, as leaving it unplugged may cause a confidential file theft especially when you are using public computers.[via]