That's happened a couple of times during my commute. I don't see any reason to take on about it. Maybe if the guy's waving a knife or something, but that'd be cause enough to worry whether he's preaching or not, out of my book or any other.

Sometimes people go around trying to sell stuff they've half-inched off a store shelf, too. Welcome to public transit, where there are other people living their lives just as you're living yours. Different lives, of course, but that by itself need not be cause for fear. I'd even say it should not, but I suppose that's not for me to decide in any case save my own. In any case, I hope I can be forgiven for thinking it rather silly to evacuate a train because someone's got the word on him.