I wondered about this with the case of the german woman who was detained for months because she had tattoo equipment. If the logic is that she will work in the US, and take work that would have gone to an american tattoo engraver, that effort to prevent loss seems to be massively undercut by the expense of detention.

Prisons cost hundreds of thousands of dollars per year per prisoner. Keeping someone detained for months is going to cost tens of thousands of dollars, at least. Immediate deportation would be the most economical solution to someone attempting to enter without a valid visa.

This is again an indication that the effort isn't to save money, it's intimidation, possibly mixed with aiming additional revenue to the private prison industry.

In the case of this canadian woman, there doesn't even seem to be any indication that she was attempting to enter on a misleading visa type. It's just pure bullshit by DHS.

I live in San Diego, even crossing the border from TJ with a US passport entails dealing with some asshole being unnecessarily abusive. They seem to intentionally hire abusive people, and encourage abusive behavior on the job.