And the place was infested with screaming children, including one who was being allowed to randomly snatch trays off the sushi boats that were then returned to the display by a parent.

This behavior is appalling to me. I have seen it before in sushi restaurants, it makes me irate. If the restaurant staff doesn't immediately ask them to leave or otherwise indicate that this is unacceptable in their place of business (not to mention taking the sushi off the display and making them pay for it) I will immediately ask for my check and add the restaurant to the list of places I will never visit again. Talk about unsanitary!