It's because even the refs know your blokes use strategic penalties, and this knowledge subconsciously resolves into seeing the other team giving away less penalties. Same way the refs belief that our blokes are crap subconsciously resolves into seeing the other team giving away less penalties. The refs should be insulated as much as possible from what they think they know about teams and players, and focused as much as possible on the rules and reffing based on what actually happens in play.
Again though, that is all on field. Off field is a different sombrero, I mean cap, I mean matter.