When my child is rude, and I make her apologize, and you say "Oh, it's OK." It is NOT okay. It is not alright for my child to be rude, whether intentionally or not, and to not have to say "excuse me" or "I'm sorry". It is not ok for her to think that she can get away with it.
YOU may not care if your children have manners or not, but I care if mine do.
So please, do NOT say it's ok when it isn't. I know you are just trying to be nice, but they have to learn. And they will not learn if no one makes them take responsibility for their actions.
To everyone else:
Groove to some Nelly Furtado. SO love this song. It makes me happy.