I went to seafood place in North San Diego County, ordered some mussels and after eating a few noticed that the majority of them still had their "beards" attached. It was a first for me, and not really appetizing.
I asked the manager about it, and he said:
1. It would be way too much work to clean each mussel.
2. If they removed the beards, the mussel's would die.
He was a little combative and douchey, and somewhat reluctantly offered something else from the menu (but no refund).
I've eaten mussel's my whole life, and prepared them at home as well (though not in years...no, make that decades!). I checked out various sources on the internet that seem to back up my stance, but wanted to know what others might think.