Interesting -- and the first TSA checkpoint to be on the baggage level. I believe IAD has or used to have a crew-only checkpoint on the baggage level:
"Checkpoint 1 is SEA’s first and only Transportation Security Administration (TSA) security checkpoint located on the Baggage Claim level, and it’s located at the far south end of the terminal in Gina Marie Lindsey (GML) International Arrivals Hall. Why the Baggage Claim level? Because space is tight upstairs! SEA is a busy, space-constrained airport, so project teams got creative and transformed available space into a checkpoint that makes your security screening quicker and more efficient."
Will admit that "Gina Marie Lindsey" did not ring a bell, but there are some news articles about her from her time at LAX.
https://www.seattletimes.com/seattle...nder-scrutiny/