Indeed, there is plenty of anecdotal evidence that “random” is anything but.
Attractive women in their mid-teens to mid-twenties seem to get disproportionately groped by male TSOs. And Muslim or Jewish presenting men almost always get “randomly” selected.
That’s not even counting the blatantly political stuff, like how the late Senator Ted Kennedy got on the no fly list for being a prominent Democrat who rubbed the DHS the wrong way.
