Yes this is controversial , five years ago definitely not . With the advent of impactor power tools that came out on the market about then and combined with structural adhesives .
The screws are a number 10 9/16 fine thread wafer screw . Ten years ago it would have taken three to four hours to fasten the pan down but with an drill , now an impactor it takes about fifteen minutes . The frame part is hardened steel so holes have to be drilled out and then the screw is driven in , on the tub or the rail side only the impactor is used. All screws , drill bits and driver bits are from industrial fastener suppliers . the quality of these from canadian tire , Home depot etc . is not up to snuff . IE a impactor bit from home depot lasts about five screws then breaks . The strength of each crew is equal to a spot weld . In engineering terms a screw is a modified wedge .
The structural adhesive is a little different with three major brands from different body shop suppliers here in Calgary with up to about 45 different grades and set up times from each manufacturer . The good stuff comes from Australia . Some adhesives set up in as little as 45 seconds on up to 4 hours and some for plastic and some for metal some for door panels and some for stuctor . The frame rails and rocker panels are considered structure . Increased strength can be added but using a mechanical lock IE adding the odd extra hole before gluing , flapper grinding all glued surfaces with 30 to 40 grit and by adding lots of heat during the last part of the set and all of the cure time.
Doors on Chevy trucks have been glued since about 87 , door panels from about the same time as well and now there are cars out there that are glued together . I believe the jeep compass is glued together.