There is the 'Truth in advertising' that has teeth...so the OEMs do
pay attention on their marketing stuff
The OEMs don't lie...just pitch to the lowest denominator buyer...that believes
in absolute terms
They do NOT lie because they have legends of lawyers word smithing all of their
documentation and of course that 'fine print' that just about no one reads
MTWR is referenced...again and again and again...as an absolute for 
towing capacity...not knowing that, that fine print modifies that number...  :S :R 
Of course do NOT forget about the 'fake half tons' made for folks who insist on
only owning a 'half ton' badged TV... :S :R :S :R :S :R
Why ask many newbies...but mainly seasoned advisors saying "a half ton
can do it"...."which half ton are you referring to???"   :S :R
Knew lots of them...but was surprised when another posted that they
had counted 14 (FOURTEEN) different versions of 'half ton' offered 
by the Blue Oval OEM...then add up the other OEMs 'half ton' offerings
No wonder so many are confused and end up counting wheel lugs...
From the mud hen +6K GVWR up to the fake half ton's +8K GVWR...and...everything
inbetween...
Finally...of course the setup and configuration(s). That is then factored
by 'experience' and talent...which, IMHO...boils down to the very
uncommon...having or lack of 'common sense'...
Know too many who would be dangerous towing a small 18' utility 
trailer with a semi...