Commuters are another prime category. Anyone else who hits a toll highway on a regular basis.
Yes, the standard static-proof bag is enough to block a normal EZPass transponder ping. Simply putting it in your glove box MAY be enough, depending on how much metal there is in the car; they want it on the top of the windshield specifically so the signal won't be blocked.
Personally, I'm glad of anything that improves traffic management data. Less adverse impact from road closures, better decisions of where to invest in road improvements, and the routing algorithms on some websites (and on many GPS units, including my own) use current road speed measurements when picking best routes.
If you folks want to opt out, fine. For myself, I'm willing to accept that I'm too boring for anyone to care about.