teal,
To be honest, I don't do the dunk test much anymore.
When I started doing it, around 20 years ago, a lot of scope had problems. Cheap scopes often leaked, and some of the really expensive European scopes didn't have O-rings in their adjustment turrets, so bubbled immediately.
These days all the scope manufacturers (or, rather, the companies that make scopes for dozens of manufacturers) that I know of seal their scopes, and its pretty rare to see one with a leak. Mostly I tend to test used scopes, or brands I've never tested before.
