"It doesn't matter how you answer, "They" already have their minds made up and no matter what you say, won't change them. They are looking for validation for their decision they have already made, and when they don't get it, they get angry at you. It isn't until they, themselves, experience costly and disappointing tow vehicle failure they will finally realize what they were warned about."
I agree with everything but the above statement. That's when they will complain that the truck was a POS lemon because the tranny was constantly burning up. I mean, obviously, it couldn't have their fualt for overloading it.