Mexican Tourist Card

I have never seen anyone mention this before. I just assumed most Mexicans were paying this tax too, and in most cases not bothering to apply for the refund either, because I've never seen a way to opt out when buying a ticket. But what you said makes a lot of sense.

I just looked at the receipt for my last round trip ticket (Mexico to Canada) to confirm this, and it's true, there's no Mexican Tourism Tax (UK) charge listed. But instead of the UK tax, there's another tax code, UK2 on the Mexican origin reservation, which doesn't appear on the past Canadian origin reservations I checked. It doesn't appear on one way reservations Mexico to Canada either.

So instead of a CAD 34.32 UK tax charge, there's a USD $29.05 UK2 tax charge (which is actually more than the Mexican tourism tax at today's exchange rate). Does anyone know what UK2 is? I spent a few minutes on google but nothing relevant comes up.