What it means: A Tesla worker says a supervisor and security guards asked him to leave the factory after handing out pro-union flyers.
He went to the National Labour Relations Board (who are there to fix stuff like this for workers, or at least try), and they said if his statement was proven true, that would constitute 'unfair labour practices' and Tesla would be in some trouble.
Elon Musk, CEO, says he's not done anything to stop workers from unionising. He doesn't necessarily think joining the union (callled UAW) would help anything: "They drove GM and Chryslter into bankruptcy and lost200,000 jobs...Tesla took over and now it has 10k+ jobs."
Whether or not he's right, workers still got a right to join a union according to the law – so the case is going to court again this week.