Idk, if you meet someone from Pennsylvania, do you ask if the person personally knows the family of the Trump assassin? If you meet someone from the UK, do you ask if they're royalty? That's the kind of odds I'm talking about, the chance is so remote that the question isn't worth the breath to ask. It's not like asking if someone identifies as LGBT (that's like 7-8%), it's like asking if anyone in their family was struck by lightning.

The main exception here is if you live in China (~3% chance of a Korean being from N. Korea) or Russia (more like 30% chance of being N. Korean). Pretty much everywhere else, it's going to be a fraction of a percent.