Testers unfortunately aren't treated very well, and some of them are just too ticked off to care anymore what's going on. Some of them just rush the door at the end of the day when time is up. Also, there is a reason most game dev's have a hard time going after pirates, those guys simply erase all traces of serial numbers…
I have often played the Devil's Advocate in discussions relating the piracy et. al. However I have always considered early leaks to be heinous. I can seriously see the harm to the developer that could be caused and seriously, people need some patience, if paying customers have to wait then so do the damn pirates, just wait…