Since this is being studied so thoroughly, I'm guessing you guys already knew this, but here goes: it feels to me (with an SNES or top-loading NES) that if the game was slightly tilted, you might not get the same conductivity. So if someone took out a cart to blow on it, then replaced it, they might replace it in a way more properly aligned to be read.

I do this with with an old copy of SMRPG - the cart can tilt back and forth a bit while "secured" in the SNES, and booting it up with it tilted one way is usually more successful.

So maybe this explains why people thought blowing was successful, along with the whole water-conductivity thing?