account_location question

I'm trying to setup subdomains using account keys (user1.example.com,
user2.example.com, etc) and am using the account_location plugin. I've
got everything working properly. My only question is, how do I handle
invalid subdomains - for example, if I only have 2 accounts (user1 and
user2) and someone trys to visit user2.example.com --

Right now the page just hangs and cannot be displayed. I'd like to
redirect them to login or provide an error message.

Thanks.