Originally posted here by nihil
Not a good idea IMO



And giving a heads-up to the thief?
I was thinking the same. When you want to catch the guy/girl who stole your laptop you don't want him/her to know that you know he/she has it. Otherwise he/she could just whipe the hard drive (assuming you can do that with a mac ( I don't know anyone with a mac so that might sound stupid, either way)).
A silent program that hides, like a rootkit, would be the best solution.