I'd say about half the problems posted by new members would be more quickly solved if users had their location listed in their profiles. This is particularly true in the Electrical forum, where code varies a lot from one area to the next. I know the idea of forcing people to put their location slowed down the site too much (ie. people sometimes chose not to sign up instead).
Instead of requiring location, how about some big bold letters on the signup screen? I bet, when signing up for sites like this, people just want it done quickly so they only put the critical info...name, password, etc. They may skip by Location just out of convenience, not because they don't want to share.
Something right on the top of the screen saying something like:
Code varies greatly by geographic location. Please provide yours to help others more quickly find an appropriate answer to your question!
Though, at this point...Dave probably has a "Where are you from?" macro