And inbound is only because they have installed kiosks that they guide everyone to. Otherwise if you go to a CBP agent they don't take your photo if you're a US passport holder. The kiosks are an end-run around tradition/rules about how CBP can treat Americans.
> they don't take your photo if you're a US passport holder
This is very much in the "you don't have to go through the body scanners" at the airport category. By default they take your photo and fingerprint, even if you're a US citizen; the specific language on CBP's website is:
"At this time, CBP does not require U.S. Citizens to have their photos captured when entering or exiting the country. U.S. Citizens who request not to participate in this biometric collection process may notify a CBP Officer or an airline or airport representative in order to seek an alternative means of verifying their identity and documents."
> By default they take your photo and fingerprint, even if you're a US citizen
Photo, yes; fingerprint, no. Every customs station I've been through when re-entering the US has taken photos but not fingerprints. (They do require fingerprints from non-US-citizens.)
