To continue, Thanks to Tesla for the links, very interesting items.
Dana has some good points with references, but...it's not within the NEC jurisdiction.
Ghost indicated a real life situation of a ceiling collapse with only a few minor injuries, because the lay-in fixtures were independently secured.
All that said, I can only enforce the NEC. The Building Inspector has to enforce the Building Codes as adopted within the NJ UCC.
BTW, most sparkies here do support the lay-ins, and secure them to the grid.
