I feel like a lot of the Japanese restaurants (at least around here, anyway) are pretty much the equivalent of typical Chinese restaurants in America-- you know, mildly authentic cuisine, but the sort of thing that's tailored to American palates. They all seem to serve the same dishes, for example, and they're pretty much all run by Chinese or Korean people since we don't exactly have a huge Japanese community nearby. They rely on the fact that the average American usually can't tell the difference.
As for pronunciation, that's pretty much par for the course with any "ethnic" restaurant in the U.S. I'll usually ask if I'm really stuck on something (despite growing up with an Italian grandfather, I'm terrible at pronouncing most Italian words), but my love of food means I usually pick up information in my reading, where there are handy pronunciation guides.
I do still laugh on those occasions when I hear somebody mention guacamole and it comes out rhyming with "Whack-a-Mole". Really, guys? Really?
"And we are all told from the moment we open our eyes, that everyone is entitled to his or her opinion. Well, thatís horsepuckey, of course. We are not entitled to our opinions; we are entitled to our informed opinions. Without research, without background, without understanding, itís nothing. Itís just bibble-babble. Itís like a fart in a wind tunnel, folks." --Harlan Ellison