Originally Posted by weero

Spot on.

The official reason why the US 1K lines are no longer allowed to accept foreign credit cards are the minimally higher surcharges these cards imply for the seller (SQ illegally solves that issue by issuing the tix in your home currency at a very
disadvantageous exchange rate ... for you).

However if they do not notice it, it always goes through smoothly. I always buy my awards from the US line, and united.com doesn't notice either of a credit card is alien.