Depending on how ostentatiously (Which I know isn't the right word, but I think conveys what I'm trying to evoke?) you were eating the meat, it would bother me. The type of meat would also make a difference to me. I know vegetarians who are bothered if you eat any meat near them. They are obviously polite about it, (I certainly never say anything) but it might bother people more than you realize.
how ostentatiously
Not at all -- not that I tried to hide the fact that I was eating meat, but I tried to be as nonchalant as I would be if I didn't know they were vegetarians. OTOH I'm not terribly good at hiding emotions, so probably some of them could tell I was feeling a little embarrassed.
The type of meat would also make a difference to me.
What kind of difference? Pork vs beef vs chicken? Steaks vs minced meat? Free-range vs factory farmed vs hunted (but how would you tell)?
If it's worth saying, but not worth its own post, even in Discussion, it goes here.