I haven't found
any hacked servers yet. And i don't think i've come across any hackers. Might be because i like the third person modes...
I went on a server the other day. And i was invisible! :O That was weird. I couldn't do anything except run, until i came across someone's gun. Pressed F t pick up, and i could play normally... minus the fact that no one could see me, and i could stand in front of a stream of gunfire and not be hurt (although my screen was permanently covered in blood like when you're really hurt...).
It went away the next round... must have just been a glitch