When ask to define pornography, a chief justice of the supreme court famously replied: "I know it when I see it." I believe that this silly tactic needs to be looked at on a case by case basis in order to determine whether it is truly stalling or not.
The technique here is harder to objectively define than a banned use of the rising pound. If player 2 is trying in earnest to hit player 1, but cannot due to the use of player 1's tactics, and player 1 refuses to engage in combat himself, then you have a case of stalling.
If you look at how stalling is defined by smashboards, you see it looks for actions surrounding the intent of the player. If the intent is to wear out the clock, it's stalling. If it's a move that is extremely difficult to counter/impossible to counter once it lands, that is not stalling. Hence why there is a damage limit on infinite throws, to ensure that the intent is not to burn time, but to take off a stock.
What that G&W was doing is known as a dìck move. It's not a way to make people like you, but it's a tactic to win matches. If approach is impossible or near impossible, that is one thing, and it should be looked at differently than just simple stalling. Example: Melee Rising Pound. Approaching a jigglypuff who is off a stage and using rising pound is nearly impossible. The risk is absurdly high with no real chance for reward. The only logical step up would be to use jiggs in a tourney match, get ahead by a stock, and then rising pound for the rest of the match. The highest level of play would thus devolve into stalling matches, seeing who can stall best.