we were using them in guam for a bit until they upgraded to sigmas. if the question is concerning using anything other than the SET-400 or Master main (or whatever strong says you have to use) there should be plenty of others adding to this. My home DZ did (though not icarus mains) for sometime until they upgraded to sigmas as well.
As far as I can tell the FARs do not prevent you from using another main, and have not since the "experimental" thing came off. There is a strong argument that Strong Enterprises efforts amount to predatory trade practices.