Actually, my dad used to do that when he went from driving a manual transmission to driving an automatic when he bought a new truck. Old habit of having his foot on the clutch I guess.
The first new car I ever purchased was a 90 Honda Accord. I was friends with the Sales Manager and he related a story about a guy that brought his automatic in for service work and was given a brand new manual civic as a loaner. The dealership asked him twice if he knew how to drive manual and he assured them he did.
He drove right out of the dealership and onto a highway. Ten minutes later he called the dealership bitching that the car had died.
Turns out he drove it on the highway at speeds around 65-70 mph - in first gear
He didn't know how to drive stick after all.