Fine Hotels + Resorts® (FHR) program benefits are available for new bookings made through American Express Travel with participating properties and are valid only for eligible U.S. Consumer, Business, and Corporate Platinum Card® Members and Centurion® Members
Nonetheless, it's not difficult to imagine that some people have success "showing" their Platinum card at participating hotels, and intimidating staff into coding a booking as an FHR stay or providing similar benefits, because there are many such programs and some of the benefits incur no direct monetary expense. (The booking requirement has been in place as far back as I can find discussions in 2001.)