There's something vaguely extortionate about "pre-tipping". I feel like my Subway sandwich or coffee might have some spittle in it unless I hit the 20% option. Rather being than a reward for good service, it's now a threat of sub-par service unless you cough up some cash.

That said, being a service worker suuuuuucks and they have to deal with an unlimited amount of self-entitled idiots on a daily basis, so I don't really begrudge them the extra salary.