If you travel internationally, you hear that question upon your return to the USA. It's usually followed by "bringing anything back"? But other than when you clear customs in the airport, you've probably never had to verify your citizenship, either verbally or with documents. It might surprise you to know, though, that those of us that live near the border get asked this question more frequently. In fact, the Department of Homeland Security has established checkpoints within our borders, and if you're traveling through the checkpoint, you will be asked to verify citizenship.
When I leave Mission, Texas to drive to either Austin or Houston, I pass through the checkpoint in Falfurrias, Texas. On a good day, I'll wait 5 minutes at the checkpoint. On a bad day, like a holiday or during rush hour, you can wait 30 minutes or more. I've never been asked for anything more than to answer 'yes' to the citizenship question. Yet it bugs me to be stopped within our borders. Apparently it bugs other people too. And they're practicing civil disobedience at the checkpoints, and documenting the experience:
Many of you might say "why do you care if you don't have anything to hide"? And others might say "they're stopping the illegals, terrorists, and drug runners". And I would say that I'm not comfortable sacrificing my liberty, even in such a simple way, to stop these crimes. It's not because I don't believe they're crimes. It's because stopping these crimes is not worth the sacrifice of even this small amount of personal liberty. It's the same reason why we shouldn't let our homes be searched without warrants. It's the same reason why you can't be indefinitely detained without being charged. It's one of the reasons that people fight to retain the right to bear arms. Because the more we freely give up, the more is taken.