Wow, I guess I’m not the only one this has happened to. I’ve been inspected or forced to jump through some additional hoop 90% of the times I’ve gone through airport security. It has been going on for as long as I remember, and happens regardless of which country I’m in.
I’m not sure what it could be, since I never get double inspected the same way twice in a row. I’ve had devices swabbed for chemicals, pat-downs, being made to walk through the metal detector multiple times (3+), and even standing still while a bomb-sniffing dog walked in circles round me.