Salesman are salesman - I've long gotten over being surprised, or angry, at what SOME of them might resort to to get the sale. They have families to feed, as well.
But, what I think bothers me more than the salesman is the buyer who, as someone else already noted, comes to a forum after having already bought asking whether or not their existing vehicle can tow the trailer/camper, 5th wheel, etc. And, what's worse, is when a potential buyer does ask beforehand and is discouraged from using their existing TV but, then, doesn't want to listen to the people from whom they've asked "advice".