Only it isn't a "fact".
It's your claim unsupported by evidence. That's "hearsay".
In that case, your argument is just as faulty. So because YOU haven't seen someone cheat/hack/exploit means that no one has ever done so? Right.. because you're the authority on these sorts of things. Maybe if your font color was yellow or whatever the BW posts are, then you'd have some authority.
But hey, you don't have to believe me. Just go on youtube and look for yourself, there are plenty of examples of people using hacks in PvP, and plenty of instances where players have gotten banned for using said exploits/hacks.