Dont listen to this guy... he obviously has no experience with hacking.
Responses:
If one player reports you, blizzard will have to check to see if you are hacking (normally watch you do it).
If blizzard runs a background check (dont think that they can do this with the current version of warden), they will find nothing. WI is not currently detected, not even on live servers.
The third one he says doesnt even make sense... I mean... why the hell would they ban people for using a program, and then later on say... "Hey, theres been alot of bans from people using this program, lets ban everyone using it!"
EDIT: Oh yeah, and a ban on the PTR does NOT mean a ban on live servers.