I have never heard anyone mutter about me in an Asian restaurant. The difference is that they're usually muttering about somebody who is using chopsticks incorrectly or committing some other faux pas because they don't understand the table etiquette of the chef's culture.

For example, many years ago, I was in a Chinese restaurant in London, and there was a businessman in an expensive suit eating at one of the tables. He was being muttered about.

I walk in, sit down, order my food, start to eat. The waitress gives me a smile. The businessman looks at her, looks at me and horror dawns.

In Chinese traditional service, it's a no no to eat directly off the plate on which your entree is served. You transfer the food and the rice to an eating plate or bowl, combine the two, then eat. This guy didn't know that. He didn't realize until he saw me doing it correctly that he had made a faux pas. (In fact, traditionally, Chinese food SHOULD be served what we call "family style" and there's nothing better than doing that with good friends).

In other words, if the waiter is muttering about you, you may want to look around because you are likely doing some small thing wrong. (It's not just Asian restaurants. Americans get British pub etiquette wrong all the time too :P).