All I know is that it's already crowded back there. As a ref I've found it hard to get from side to side (not much room at MWR - others could be better/worse) The players have to walk a tightrope when they go back and forth.
As for all the anecdotal evidence as to how it's worked out fine, I've already seen a student, who wasn't supposed to be running, take a header over something that wasn't supposed to be there. Knocked the wind out of him
