This from another thread, and as if true, relates directly to security. It is rumored that IAD is not conducting electronic verification of BPs for Precheck.
Originally Posted by
exerda
At IAD on Sunday, I noticed the Pre line no longer actually checks / scans your BP at all (there is an airport employee at the head of the line who glances at your BP for TSAPre logo, but that's it). They now scan your ID and don't bother to confirm it matches BP at all (interesting, if logical in real-people thinking, just not logical in TSA thinking). But that is fodder for another thread--just have to find the right one...
If TSA has instituted this practice, then Precheck is a confirmed useless smoke and mirrors program. If the ONLY confirmation for Precheck at IAD is visual and TSA is not matching names to BPs, then what a crock TSA is and what a crock Precheck is.