You think tarots are only known in the US?

You also must be American.

Tarot were initially invented in Italy centuries before your country even existed. It is well-known all over Europe. Including German Grosstarok and modern examples such as French Tarot and Austrian Königrufen. It is now used all over the world. The US is but a small blip on its history.

So no, you can't tell they are American.