In that case, I know if I was going to steal a laptop, the first thing I'd do is format it. Do any of the programs remain after a hard disk wipe?
Also, for those using the Prey panel - why does it have an option to save your password? If you're still logged in when the thief makes off with your laptop, and he has any knowledge of these kind of programs, they'll just log in and deactivate your account or change settings.