over here you get a pita with a bunch of falafel balls in it, then you head off to the salad bar to fill it up with as much vegetables, hot sauce, garlic sauce, whatnot, stuff as possible.
i'm pretty sure that's not very authentic either.
but the falafel joints pride themselves on being vegetarian here, attracting a certain slice of the population etc .. at least, the ones i've seen. good possibility that, for example, in amsterdam they sell falafel with shoarma and call it doner.
hell, even when i was in turkey they sometimes got it wrong. doner means "turning" and kebab means "onna stick" (at least, so i've been told), referring to the big hunk of meat that's turning onna stick, little scraps are cut off.
but seemingly, you can call anything based on little bits of meat "doner", no matter if it's from a stick or if you're gonna put it in a pita, or whatever.