I've always wondered about the rationale behind this.
We know the TSA rarely has rationale. So can anyone explain why they have an ID checker to let people into the security line, and then require the boarding pass be displayed at the WTMD (which is often less than 10 feet from the WTMD)?
How does the 2nd boarding card display at the WTMD improve security? It surely slows people down, since they've got their hands full, taking off shoes, taking out electronics, their liquid baggie, jackets, etc etc.
Why why why??