I followed a link and followed a link from there and... eventually ended up at this video about an adopted lobster, and I learned a lot about how lobsters work. Huh.

Keeping a grocery-store lobster as a pet (YouTube)

I didn't know (having never been in the market for live lobster) that they banded the claws like that, apparently for extended periods of time and apparently causing pain along with loss of function. Granted, loss of function won't end up being the largest problems most lobsters in that tank face, but the pain is still a problem IMO. This one had been restrained long enough to cause visible injury, so it probably wasn't just done that day.