I thought the same thing but with the way that the bottom curls around the frame really stiffens it up and locks it in. There's 6 bolts along the frame and then 2 under. There is a hole for an additional bolt all the way to the front but you have to drill your frame and I don't think it's needed. If I see any movement which I doubt, I'll add the additional bolt.
I figured with the wide flares on the Pro I'd need the added protection for off roading and to help keep the rocks off my paint from road debris.
Weird, if I put a scratch in it from off roading I'm like "oh well, that sux" but if I see where a rock kicked up from the road and nicked the paint. I'm pissed...lol