Subject: Re: Welcome to Chinese Operatives
Because they're trying to blend in. Blend in with who? Thanks to the current situation, literally everyone is rushing to the border.

You're going to be singled out for some extra questioning and some extra background checks. Which anyone capable of bluffing their way through that should be flying in, not trying to walk in.

And if your facial or other biometrics aren't on some terror watch list, then what?

When there's 10 people a month showing up at the border, then what you're describing will catch people. But not when things as they are now, with many thousands times that flowing in.