Not sure if anyone has seen this article, but its an interesting story and worth a read:

http://expertvagabond.com/tracking-stolen-laptop/

The guy had is macbook stolen, only to recover it 3 months later from Panama after he'd returned to the US by using laptop tracking software and outing the laptop thieves / purchasers on his blog. 

great story, off to check out Prey.

i did install it after reading..

It seems can be misused as something to invade privacy of someone.