CBP proposes to require mug shots of all non-US citizen travelers
papersplease.org
papersplease.org
So, ask yourself just how badly you want Americans treated abroad (including diplomats), and make sure you don’t treat any travelers to the US any worse than that.
Another facet is that mistreatment of non-citizens is usually a proving ground for the hostile policies, that Gov will eventually want to deploy against everyone.
Kuwait collects DNA.
Perhaps CBP could just get non-citizens to preemptively serve jail time, for the unmitigated gall of being a non-citizen.