I normally give the benefit of the doubt, busy, short on staff, but I came in only looking for a couple of quarts of oil. Michael behind the counter didn't seem to be in the best of moods so I really didn't try to strike up a conversation.
He rang me up and I gave me the total and swiped my card, I then asked if he was going to ask for my rewards customer number which I use quite frequently so I know the process. He begrudgingly said I normally would ask for it when it's not busy, I believe I was one of two customers in the store. So he had to reswipe my debit card again so I would get credit for the transaction.
Just a reminder if you don't say it they won't always necessarily do it, I can't speak for other employees just for Michael.