I'm a vegetarian and I wouldn't cook meat for a meat-eating friend. I have no objection to them eating meat (my father was a pig farmer, so I grew up with the idea of slaughtered animals), but I hate the smell of meat, raw or cooked, and I couldn't touch meat to cook it.
I do find it odd on some editions of Come Dine With Me, that some vegetarians will eat fish, chicken and even bacon. They are demi-vegetarians.
I do love Come Dine with Me, one of my favourite shows.