The computer this drive is in is frequently & abrubtly powered on and off by its users
Doing this, data loss is only a matter of time.
Each time an ext2 or ext3 FS isn't shut down probably, during the next reboot a FS check should be done (most distros do this automatically).
Or try tune2fs -c<n> <dev>
to check the FS after <n> mounts (man tune2fs
The best solution is to "educate" your users to shut down the box in a proper way.