I have no issue if they REALLY HAVE to check the bags.
But I can't count how many times I've boarded the plane (I typically check a bag) and have seen empty overhead bins after they already forced bags to be checked. It has to be at least 50% of the flights I'm on.
Bags lined up by the jet bridge door way waiting to be loaded when there are numerous bins open.
Then the flight attendants just go and shut overhead bins - that still have room.
It just makes the customer unhappy and the ground crew do more work.