Employees at a Michigan Smoothie King refused to serve a Donald Trump supporter and his wife ... and the contentious argument between the smoothie makers and their would-be customers is all on video. Check it out -- Erika Lindemyer recorded the tense encounter at the shop in Ann Arbor on March 1 ... she argues with a woman behind the counter, calling her refusal illegal discrimination. The employee snaps back that Trump doesn't support her ... and she therefore doesn't feel comfortable serving