As I mentioned in my response to another thread on the topic, my concerns regarding this are as follows:
1. The concern of having to provide biometric identification (possibly). I see this as perhaps leading to a scary situation where people feel that they have a choice of either providing biometric identification or being groped.

2. The concern that it will make it more miserable for everyone not a part of this program. I could see airports with a few WTMD lanes making those lanes only for people a part of this program. This program perhaps leads to everyone else not having the ability to self select a lane with WTMD.