Some vegans. If you care about the environment at all you’re not going to be demanding every restaurant buy additional grills, expand footprint, or alternatively not serve vegans at all. Demanding separate grills doesn’t have any impact on animal suffering either. The only vegans I could see caring about that are the purity test vegans or the vegans who are convinced meat is physically dangerous to human health, and those people shouldn’t eat in McDonald’s regardless.

This used to be a concern for me earlier on in my vegan years but I soon realized that veganism isn't about eating a "pure" diet, it's about the animals. The best thing for the animals is for these products to sell and I shouldn't let a little cross contamination deter me from that.

As an ethical vegan (reduce animal suffering but previously enjoyed eating meat) I don't care if it shares the same grill or goes into the same fryer. But I'm also unlikely to go somewhere where that'd happen - it's more likely if I'm pressed for options i.e. somewhere out of the city.

I'd give the McDonalds burger a go though - it's always interesting to see how far food tech can be pushed and how different it is from the real-deal. The key in my mind is synthetic collagen to give fake meat the bounce/snap/chew of real meat (FWIW I don't eat fake meat often, just interested in food tech in general).