Allow non-BK users to query location via SMS

How about adding the ability for non-Britekite users to query "WHERE USERNAME" via SMS, and reply back with location based on privacy settings? For example, a friend who isn't a BK user wants to know where I am, he can text "WHERE XTEX404" to the BrightKite short SMS, and based on my privacy settings (and other settings), he'd get back the location (or even better - a google maps link so he can pull it up on his phone).

I know the ultimate goal is to get people to actually join BK, but this might be a good way to "tease" people with the service without them having to create an account. Maybe limit the number of requests per phone number - once you go over a certain number, you have to join BK? :)

This would definitely have to be limited in some way, probably 'x' per hour from the same number, and it would have to be configurable by the BK user (turn it off completely, only return location, return location/note, return Google Maps URL, etc). I might go as far as adding a "block these numbers" list (with wildcards?), but that seems like an awful lot of work.