Not that many .
Actually, I have seen so many hackers in kitpvp , but after the big reset of kitpvp , it is almost impossible to see them , even if you see them hacking they will get ban after 2 or 3 min of a fight , I have seen so much of them got banned in the first 20 sec of fight vs me , e.g. 2 hackers have teamed to kill me to get my set , and when I was close to get into the fight , and at the first 3 hits to them (they had no kb ) , they got banned .