I've been to a restaurant with a friend once who hates cilantro. She ordered a meal and said she did not want any cilatro in it. Then she got her meal and she thought there was lots of cilantro in it and complained about it. The waiter said: "Ah, but that is not cilantro, it is XXX." I forgot what it was called. But apparently, there is something that is similar to cilantro (look-wise and taste-wise).
It was a Vietnamese restaurant. So if you go to a Vietnamese restaurant, you should point out that you do not want anything that even remotely resembles cilantro.