The copper ambassador effect is probably too strong, also considering that Banshee is nonterminal. Fact is, ambassador tends to slowly thin (2p) or slowly junk (3-4p), so it's getting the game somewhere. In 2p, banshee (bar other trashing) is only moving copper around, so you'll get the copper table tennis thing, only nonterminal and infinite. I'd be extra careful when testing this.