I know a photo taken by a pro photographer when I see one.
Um. I know a photo taken by someone who knows what they're doing when I see one, but I can't think of any way you'd identify them as a pro, as in someone who makes a living at it. There are amateurs who could make a living as pros if they wanted to, and there are pros who somehow make a living despite not being all that behind a camera (probably because the "taking pictures" bit is just one piece of the jigsaw). Just because a photo is of a professional standard doesn't mean that the photographer is a professional.
I'd be staggered if anyone had ever employed a pro photographer to put in a BOTM entry, that would seem mental.
Anyway. The thing with BOTM is that there are no criteria -- some people are voting for nice pictures, some for favourite brands, some for perceived effort, some for bikes they'd like to ride and I dare say some just for their mates, but it all counts. The beauty of that, of course, is that there's no sure-fire way to win, which is a good thing