Not on PBBans-streamed servers. 80% of them are clean (A-O-D, NANO, etc). I play on those kind of servers every day.
Here's how they work:
A player with undetected hack joins a PBBans-streamed server. PB and the PBBHub don't detect it, an admin/mod bans him manually. This ban along with the last 8-digits of the GUID is streamed to THOUSANDS of other PBBans-streamed servers in a few seconds. Next thing you know, he gets a GLOBAL GUID BAN. His Key Code is worthless, he can't even play on Cracked Servers (with each day passing by, more and more get banned by PunkBuster).
Servers that aren't streamed are usually full of cheaters because admins don't care.