It doens't really matter. Sometimes people just want an answer, and they have to sign up to do it so they do.
Possibly creating a system like MSN do, where after an amount of days, the account automatically deletes, until they have a certain post count, and then it stays. Like maybe the first border of acceptance. Not just a newbie.
But yeah, i tihnk we have a close community here, of most people that will stay to help. Thats all that matters in the end