For the first time in months, I flew an airline this morning that I have no status with (United out of MKE) and my boarding pass was marked with "SSRS none" where an SSSS notation would normally appear.

The SSRS was highlighted by the airlines ID check prior to the TSA section of the checkpoint, and the BP was passed between two different TSAers, but I didn't receive any additional attention beyond the BP double check.

Anyone know what the SSRS notation means?