Parental Control time limits cause crashes

I use Parental Controls to limit my own time, as silly as that sounds. On 2 occaisions, when I have awoke the laptop from sleep and entered my password after the ending limit time, the laptop has shown a blue screen. The mouse works, but no function key response, ie. volume control, display or keyboard brightness, etc. A CD is spun up, then ejected. I've tried <ctrl>-C, <ctrl>-\, and all combinations of <ctrl>, <shift>, <option>, <esc> and <command>. The laptop does dim the blue screen and go back to sleep after the expected period of time. The next day, after the starting limit time, when the laptop is awoken, same blue screen. A hard reboot is the only rememdy.

Also, if you extend time twice, you get more time than requested.

I've quit using Parental Controls.