There have been a LOT of issues caused by OSX Lion updates, including other apps inadvertently locking Macs. To solve some of these issues, or rather to help figure out whats going on, we have included some sounds (whose volumes you can change in a new Sounds tab in settings):
Lock and unlock chirps into TokenLock.
USB Device insertion/removal sounds.
Warning beeps when a Bluetooth Device is out of range.
Now you'll KNOW when its the culprit locking your Mac!
We have also added update notices to the test/demo versions of TokenLock - so the app will let you know when we have posted another version.