Good question. Maybe they're waiting for the first month to be over... considering everyone is on their free 30 days at the moment. Why go through the hassle of restricting players from using alts they already made that don't wish to pay for them? Easier to restrict them now and then unrestrict those who wish to pay for them. They already have loads of people that made alts during open beta that they have to deal with. Could always go prepay for a month as an eight character sub and see if it unlocks it for you. I really don't know though, that's just my guess at their reasons.