Seems there are a number of versions of these machines cropping up.
On arrival at the new DFW D ( International Terminal ) last week, after I refused to take my Eccos off (the soles are about 1/2 inch) I was told by the supervisor that I was selected for exactly that refusal.

Sent over to the machine which consisted of glass sides and entrance and exit doors which closed automatically a short time after I entered and opened again after the puffing. The entire process seemed to be automatic.

As much as I hate to say it I would much rather deal with that than the pat-down, at least I dont have to listen to any BS from the machine.
mike

P.S. they didnt require me to remove my shoes