Its allowed but discouraged. Theymos doesnt like it, but sees no way to prevent it.
Some may this as bad, but as a loaner I see this as good, since I take accounts as collateral. And since actually 100% of my loans have been given with an account as a collateral, this is important for me.
I dont see it as a problem either, just giving the forums stance. I think its good because it helps to remind us that we cant trust anyone here just because they have a certain rank. I also hope, but that might be wishfull thinking, that the majority of account deals are for signature campaign participants. Higher ranks earn more and to have invested in an account discourages spam.