If the tablets just had a standby mode like Palm/WinMo devices then none of this would even be an issue. There is no reason to keep the devices running 24/7 since they don't receive phone calls, and turning it off and on again just takes too long.

I will be testing it out though, seeing if there is any drain in offline mode. It might also just be that hte battery was damaged since I often charge it from USB.