Jimbog1964:Multis are an issue, but my ? to the OP is how are you deciding one is at legend tier? No names or anything.
In a lot of cases, when a legend has a problem with multis, it means they're beating his other lower tier accounts ;-) I doubt this is the case with the OP though, probably just a case of "these guys play better than me, so they're not legit".
But there were some real m/as to be found at legend tier. a couple of people were promoted to TL tier in waaaaaay under 500 RR because of it, some accounts were also closed. That's how MS became ZX and got promoted to TL in under 200 RR total (all tiers combined) ;-)