If time travellers visited modern Earth what tiny thing would expose them immediately

[Zach]

People imagine time travellers failing because of major historical mistakes, but honestly I think tiny social details would betray them almost instantly

Someone from the future would probably panic slightly while pretending to understand how printers still work

Also imagine them trying to act natural while seeing everyone willingly carry tracking devices everywhere

[Red Builder]

Couldn't agree more. Could not agree more.

The best advice usually starts with it depends, which is frustrating but honest.

Thanks for that