From my flying experience, “having an offensive odor” is NOT a criteria for denying service. Most of us with any flight time have experienced passengers reeking of sweat, BO, goat urine and any other foul substance known to man and just pray they have not been assigned to any seat near you.
or that you have to sit in the seat AFTER they have occupied it ...
yuck
I flew from Heathrow to Newark once where the gregarious Brit in the seat next to me was dressed in a suit but had the most horrendous B.O, bad breath and dandruff. It was absolutely nauseating. I spent 7 hours with earplugs in, pretending to sleep so he wouldn’t even look in my direction. Do you know how hard that is to pull off ?