erco wrote:1) When did Costco start doing that, and
Costco has done that for as long as I can remember.
2) Is it a total scam, as suggested by Fifth Gear's video?
If you pay more money for nitrogen than you would for regular air, then yes, it's a scam.
If you're filling up with nitrogen for no additional charge, it's perfectly fine.
I can think of one small benefit - if the nitrogen really is fairly pure, it means you won't be adding any water vapor into your tire. And that means that there's less of a chance of the TPMS sensor getting iced over in the winter. I've had that happen to me - fixes itself after parking in a warm garage for a while.