Hard to think of any really.
Years ago it was commonplace for several players to have stints at Cardiff, Swansea and Newport and can't recall any being called traitors. If anything, we've been the club players have moved to, with Andy Legg, Jason Bowen and Alan Curtis springing to mind. More recently we've had a few coming to us from over the Severn, but don't think they're referred to as traitors.