Hey Mike, personally on my site, I would not force members to enter a location, but that's just within my community. If folks want to remain private, and not disclose their location, I think they would appreciate that.
In my community I made a suggestion to plot their location, and if they don't want to disclose their actual location, they can always just provide their Town Hall address or some land mark in their area rather than their actual address. Our folks seem to like that idea, typically they'll enter a land mark location in their town.