Keep in mind that there is not a riding time point in HS, so they should be looking to improve.
I have called stalemate when the top guy has a leg in and there was not a clear option for either of them to improve. The next time the top guy created that same situation, I called him for stalling.
They should be smart enough by then, to know to move on to something else.
Oh and I have never called double stalling. That just seems like a bs call, even with heavyweights. It is as bad as hearing a coach yell "FREE MOVE!"