It was supposed to be a PR stunt about No Taxes on Tips, that's why the press was all hanging around to take pictures when the Door Dasher showed up.

Then Trump comes out and the press asks him about his blasphemous Easter post, and he offered his outlandish excuse that he was supposed to be a doctor, completely blowing his PR stunt.

He probably didn't even tip her, he's a proven scumbag cheapskate. Just the pleasure of serving him is tip enough.