I do now seeing what you say I do agree with a more verbal and/or stand up and as you say "higher dog" split them up. And I have seen this many times, where my boxer would do that at a dog park, he's such a dork lol, some dogs would start arguing and he'd go shoulder his way inbetween them and just stand there.
I can also understand your point that there are a high number of boxers that don't get the clue and subtle hints, and part of it JMO is back to training. And the whacking them in the face, yep thats a boxer, lol. And I can understand that Basenjis don't like that. When we frst met our neighbor that had a Basenji, Reggie tried his normal "boxer" techniques (but thankfully he's not a face wacker) to get the B to play, pawing at him, low woofs, etc, since that didn't work he took the B's toy and stood there squeaking it at him and then took off in a game of chase, they were friends until we moved away.