Re: men ordering steaks en masse.
My group of friends are lazy, and we split bills regardless of what you personally ordered. In the old days this was called the Stella accelerator. Back when we were drinking in the union bar, Stella was noticeably more expensive than the 4% lagers, so if one person ordered Stella in a round, we'd all move to Stella.
It's the same with a steak, if someone is ordering steak, and you're paying a fixed percentage of the bill, the correct strategy is move to steak, rather than eat something cheaper, otherwise you're subsidising someone's steak meal, while you eat salad.