Granted a teleported account is a little bit different because this account authorized it, but I can see your point that a reputation here stays here and doesn't go with the name to other sites. I'm just not sure how I feel about it.
If you trust a person here, I don't see why it should be different elsewhere if that same person can prove to you the account on Altcoinstalk is also them. If Bitcointalk goes offline one day, the reputation you built here should speak some volume. You shouldn't blindly trust anyone, but it's still something to keep in mind.