The purpose of protected questions is, according to the message presented on such a question, "to prevent 'thanks!', 'me too!', or spam answers by new users." The more verbose ["Protected questions" privilege page][1] agrees on the purpose.

Considering this, shouldn't a user be able to answer protected questions if they have gained at least 10 rep on *any* stack exchange site? If they've already demonstrated one site that they are familiar enough with the SE Q/A format to not be a drive-by useless answerer, shouldn't that confidence in them carry over to other SE sites?

Or maybe at *some* level of combined SE rep this restriction should be waived. I find it silly that at 15k+ combined network rep, I'm unable to answer a protected question on a SE site I've just started using.

  [1]: http://stackoverflow.com/privileges/protect-questions