Depends on if they're at a border crossing or in the interior of the country. Laws apply to citizens and non-citizens alike. If you haven't been admitted to the country, about the most they can do is turn you away at the border checkpoint and put you on the next flight back to your home country.

and if you're a citizen of the country you're trying to enter...

Then the TSA drops a paper clip while you bend over and pick it up

No, at least, not by the DOJ, and not for any use in a court of law.

We wrote about this in our border search guide and concluded that there is a risk of being refused admission to the U.S. in this case (in the border search context) because the CBP agents performing the inspection have extremely broad discretion on "admissibility" of non-citizens and non-permanent residents, and refusing to cooperate with what they see as a part of the inspection could be something that would lead them to turn someone away. (However, this is still not quite the same as forcing someone to answer in the sense that they don't obviously get to impose penal sanctions on people for saying no.)

One reason I'll never visit the states.

If I absolutely had to I just wouldn't take a phone/laptop with me.

" they don't obviously get to impose penal sanctions on people for saying no"

I wonder if there is any negative effects associated with being refused entry by a CBP? Could it be the case that if you are refused entry once, that in the future they will be more likely to refuse you entry? If so, that's a fairly significant penalty/power that the CBP person has.

> I wonder if there is any negative effects associated with being refused entry by a CBP? Could it be the case that if you are refused entry once, that in the future they will be more likely to refuse you entry? If so, that's a fairly significant penalty/power that the CBP person has.

Yes, some categories of non-citizen visitors (I don't remember which) are asked on the form if they have ever been refused entry to the U.S. (and are required to answer yes or no). If they're using the same passport number as before, CBP likely also has access to a computerized record of the previous interaction.

Plenty of countries will ask if you've ever been refused entry to any country. And you're also generally automatically excluded from any Visa Waiver Programme from then on too. So it's a major issue.

> If they're using the same passport number as before, CBP likely also has access to a computerized record of the previous interaction.

(They might also be able to search their database by biographical details such as date of birth, so getting a different passport may not prevent them from guessing that you're the same person.)