I realise that, but it still means (in theory) that someone could get to Platinum by taking just 4 short domestic rtn flights, if they can get enough SCs pooled by others. That's pretty ridiculous, when you consider that the equivalent flights with QF would only get you about a quarter of the way to Silver!
In practice, I doubt if many people get to Platinum quite so easily, but that's really only because VA enforce the same household rule. Imagine if you could get away with adding any extended family member to your pool any time they had an upcoming VA flight? And the reality is, if VA didn't enforce the same household rule, they would probably not be enforcing the "family" part of the rule either, so it would open up the possibility of people pooling SCs from literally anyone. I would guess that a lot of VA's customers have little or no interest in SCs, so there would be plenty of people willing to pool them to someone else, if it was possible.