Surprisingly, this has happened twice

not when they are expected. I get the concept and i agree with you on the idea but the idea morphed into some sort of bizarre swamp thing and now it really is just welfare... if a customer is gonna pay 85% of an employee's wage on top of w/e is basically in the bill already, you really thing the employer will stop that?

If the server expects a tip, they'd damn well better give service that warrants it.