I have seen mention, probably somewhere here, that a rear facing rear lever could be tapped and dislodged by an unscrupulous rider from behind. Don't know the truth to it...if it can happen without both riders being knocked off balance, but perhaps.
I place my rears between the stays and the front aligns with the fork blade. I have hex head (or safety keyed) skewers on about as many as have q/r.