Flying is not a constitutionally protected activity... see, for example, the legality of un-appealable no-fly lists.
https://www.theguardian.com/world/2018/mar/12/tsa-surveillan...
So my guess is that they aren’t supposed to do this, and if a judge ever got the case, the TSA would be in lots of trouble if found doing it.
https://www.aclu.org/other/constitution-100-mile-border-zone