[Salvation]

Now GPS purchases will require waiting periods and background checks.

I think you answered my question: Who could buy one of these global positioning devices before 9-11?
Who can buy them now?

[Risky Schemer]

Who could buy one of these global positioning devices before 9-11?

Anybody. Check hunting, marine catalogs, auto stores (GPS mapping computers), even sold as optional equipment on some cars (I believe) and boats and private planes.

Who can buy them now?

Anybody. For now.