I have one PM tag on my bag and I've had several occasions where it's made a (small) difference. Both times the "difference" was negligible but once when they were trying to make sure people got into the right line on a VERY busy travel day (economy folks had been jumping into the Elite/FC check in line b/c the economy line was VERY long) so the tag made it more identifiable that I was in the right line. Also, once when the security line was quite long and precheck was closed they were trying to move Elites to a separate line (think - "pre check lite") and the tag helped me get moved to the shorter line. Surely if they had looked at my boarding pass they woulda seen my status too but the tag just helped save that one step.