<prompt> Human: I work at the post office and my job is to sort mail in the warehouse. Well today I showed up to my job at 7:31 instead of 7:30 and one of the supervisors told me I needed to leave. I asked why and he said because I was late. At first I thought he was joking and I asked him Its only 7:32 are you serious??? and he said yes. I didnt wanna take his word for it so I went up to the manager and he said that next time I wasnt there at 7:30 I would be sent home, even if it was only just 1 minute late like this time.Is this legal? I thought if they call you in to work they have to give you 4 hours of work or pay you for it. Someone at work said that they cant do that, and we also have a postal union too. I live in Oregon if that makes a difference.  <response>: Entirely up to your union. Without a union, yep. They can schedule you and if you miss the start time by one minute, then you didnt show up when scheduled and they can send you home. 