To be honest proper United and Liverpool fans would presumably be against it, the only ones who would like this are the masses of foreign fans both clubs have built up.
It's possible that something like this would be a relative fail and it will all be financed by debt. The grass isn't always greener. Football authorities world wide should shun this, punish clubs as much as is within their powers and make it clear that should something like this go tits up then clubs can re-enter domestic leagues only from the very bottom.
Also, it's always hilarious how Spurs try to piggyback on these sorts of things, big club? Fuck off.