If you're talking about immigration and she's not a US citizen, it will depend on what country she is from and whether she entered the US with a visa or through the visa waiver program. All depends on the country.
We've gone down with a friend that's got a visa (she's from australia and not a citizen but been in the US for many years). We just brought a youngster down that had a passport card/id. At the border, it's pretty loose. If you have your US PassportCard or "green card", you blow right through. We've gone through before where they took 5 passports from me, looked at the 6 people in the truck and handed them back and waved us on. No worries - just don't expect to come back in without your docs.
We've gone down with a friend that's got a visa (she's from australia and not a citizen but been in the US for many years). We just brought a youngster down that had a passport card/id. At the border, it's pretty loose. If you have your US PassportCard or "green card", you blow right through. We've gone through before where they took 5 passports from me, looked at the 6 people in the truck and handed them back and waved us on. No worries - just don't expect to come back in without your docs.
Sorry, but you don't always just "blow right through" with a green card. My husband has a green card and 1 out of every 4 trips I get the third degree and I'm asked multiple times how I know the man sitting next to me, where does he work, etc.
Sometimes I think it depends on which agent you get.
We just crossed on Monday and my 14 yr old son doesn't have his PP card yet. I'm usually fine with BC and school ID.
This trip he didn't have it in his wallet. So I got a little hassle (with a smile).