Good catch Windson! I overlooked the tests. There is also a comment that it's liberal in the test function. Since the code was added in 2006 I don't if it's ok broken to fix this or not. I will let the reviewers take a call then. There is also domain_match and user_domain_match that perform more tests.

> This is only a rough check for performance reasons, so it's not too critical as long as it's sufficiently liberal.

Thanks for your input!