Knew a guy who worked at an indy garage near an interstate while in college. He was encouraged to employ the old famous "short stick" technique (among other dirty tricks) of checking custmers oil where you place your thumb under the dipstick flange whick makes the stick read about a quart low. They had a rack of empty oil cans with the hole on the bottom. He'd insert the spout and hold his hand covering the hole in the bottom. About everyone that came in left with at least one quart of "oil". Not a huge ripoff individually but it made the owner thousands per year. People wanting to rip you off are everywhere.

bl