review/rethink logging with no location

[mfrasca]

what should the program do, when a user starts using the program but "forgets" to insert a location code? refuse moving to results page? go to results but warn? not log the action?
I think that the least surprising would be to refuse moving to results page. if the user really wants to work without location, we could add a check (initially unset) that says "do not log", or they could insert a null code. I don't know, I think I would like to discuss it with users.