Murphy's law: you will get the dreaded SSSS or no precheck when you have a tight connection and can least afford the extra time in a security screening.

We've had the implementation amount to merely going through the regular security line rather than precheck all the way to a full on secondary screening PLUS a gateside full check that included dismantling a carryon down to the lining.

Doesnt happen often but boy when it does is it a pain