I hate being called Sensei at Judo. Too much baggage. I tried to get people to call me "coach" until someone up the food chain (whom I respect) reminded me that "Coach" is an official USJA Designation. <sigh>
Now I just make sure that everyone coming in knows "Sensei" only means "teacher" or "instructor" and, in Japan, the First Grade Teacher who looks like she should be getting ready for Prom instead of teaching, is still called "Sensei" by her students. That usually manages to communicate the concept.
Peace favor your sword,
Kirk
Interestingly, I've never had a problem with "Sensei" - I don't think it carried the "weight" in my instructor's school that it does some places. We found it easier than "Mr. Wyndham" or "Mr. Seymour", especially for new students who didn't remember an instructor's name. So, "Excuse me, Sensei" sometimes was a really formal, "Hey, whatever-your-name-is, can I get some help?"