[spidey]

Tug of war is a cooperative game, generally, not a competitive one (ever noticed how most dogs will immediately bring the tug back to you if they "win", to start the game again?). It's also a great reward for some dogs, and a way to work on your "out" command. I have no problem with tug, as long as you don't allow it to turn into a competition and as long as you make sure that you "win" when you want to (i.e. by telling the dog to let go). The idea that it "makes them aggressive" isn't really based on anything other than conjecture, and indeed, studies of this behaviour among wild and domestic dogs indicates that it's much more a cooperative behaviour than a competitive one.