1. Those are indeed socks under their flip-flops.
2. That flashing light on their rental Kia? That’s called a “turn signal.”
3. They’re going the speed limit, or some semblance thereof.
4. They notice the cacti, and sometimes even take pictures in front of them.
5. They pronounce it wrong — whatever it is. Street, food, library… Mexican Spanish doesn’t have a twang.
6. Their margarita is frozen. And blue.
7. They’re planning their half-mile guided nature hike at the South Rim.
8. They’re wearing a sombrero. And chaps. And yellow ostrich cowboy boots. And Blue Blockers. All at the same time.
9. They’re complaining about the heat and/or the “brown” landscape.
10. They’re staring up in awe of the Milky Way, the sunset, and the clouds.
11. They don’t understand roadside shrines or Aztec-inspired murals.
12. Gas station wolf T-shirt? Present.
13. They’re walking a little dog that isn’t a Chihuahua.
14. They spend the after-lunch hours in the baño.