Why is this unfair?

I've been reading some 2moons rules, and i wonder, why is this unfair;

Multiple Acclaim accounts

You can have more than one Acclaim account but you cannot use this to login more than one account and the same time and trade items between your accounts within the same game to gain an unfair advantage.

Is this Unfair advantage?

Yes it is in a way. But anyone will have more than 1 account and mostly will be in loa selling and main lvling/having fun. But as for me I am thinking its trying to say its illegal to log in muti acc at the same time aka boting multi acc. Other than that most acclaim rules are crap. It will and always get bend anyways x.x by legit or hackers XD

They just saying that so they could claim they're encouraging "fairness" if they ever get attacked for being "unfair." A lot of companies always just splurt out statements to get people off their backs but never enforce them.