I'm not positive about this but......
I always thought the CTRL-ALT-DEL sequence was required to dicourage HACKERS. It is very easy to get brute forced hacked by programs designed to try many different password patterns. However, it is not possible to do this when you must first perform a CTRL-ALT-DEL sequence. The CTLR-ALT-DEL sequence protects the system from remote hackers.
I believe it is more of a remote risk to disable this funtion then a local risk. Locally, the password must still be entered to log on. So what's the difference if an uninvited guest hits CTLR-ALT-DEL before attempting a logon? He is still in the same position...trying to guess the password.
Again, I'm really not too sure...but this is what a was told a few years ago. If your in a pretty small environment, there has been no security problems in the past, and the data isn't top secret/criticle data, I don't think it will be a tremendouse risk. But you have to make that call.
Hope this helps...
Joseph L. Poandl
MCSE 2000