And you're basing that on??
174 games without incident.
I mean we're talking about a guy who is criticised for being a soft front runner. Not really known for being Mr Physical.
Willie Rioli for example has played 18 games and has already given away more frees than Gaff has in any season. He plays close to the edge and has given away some dumb 50m penalties etc. I have little doubt at some point he'll cross the line and get suspended. Other players are niggly, others still are prone to brain snaps. I don't think it would be that hard to goad James Sicily into punching you, for example.
Every team has players that are physical, players that are antagonists etc. Gaff to this point has never been either - which is why the whole thing is such a shock.
The whole 'character' thing is all up to the point of the incident, though. You run out of good bloke points when you punch someone. If Gaff is reported for something relatively minor in future he'll see be Andrew 'left hook' Gaff,