These days, I’d assume any limits are strict - be happy if they don’t say anything, but don’t complain if you do.

Not it sure if it’s still around, but DL used to allow 1 pound over the weight. I remember going to the airport to help someone check in with them - they had two bags and one was 50.5 pounds and the other was 51.5. Agent said policy was anything over 1 they had to charge for, so they adjusted the bags until they were both exactly51.