My husband is an EMT. he got a job offer that paid him $6 more per hour and his boss told him not to take the offer, because he will give him the upcoming promotion when the senior EMT quits.
So my husband did what he said, he didn't take the job offer and waited for the promotion. Then he found out someone else got it and he obviously asked his boss wtf happened.
His boss said "it wasn't guaranteed", he was just putting his name in the hat with a good word to the senior boss. Which obviously wasn't true, but there was nothing my husband can do about it legally (at-will state). So my husband got his paramedic license and now he's going to get even more money. Just gave his two weeks notice.