Tried it many times. Never worked a single time.

Everybody appreciates service differently. Some will tip. The banker usually sees a profit for himself instead of the person who earned it, and refuses (even as acknowledged in your post and again in several of the comments) to contribute on an equal footing (i.e. refusing to put in what they think they themselves owe, even if the bank is "over" what they personally think the waitress deserves).

Sure, if everyone in the group are jerks, it can work. Otherwise, it's doomed to misdirect funds away from the one who earned them.