How can you tell if someone is a follower of the vegan philosophy?
They will constantly tell you about it
Hahaha, exactly right! They don't eat anything possibly made from an animal in their diets. I don't think I could do it.
I know, people who are vegan will not use any animal bi product. Even soaps that use animal products. 
Yeah, those are your "ethical vegans" and I think they're a bit more of the militant type with their philosophy.