-- oh absolutely. I think that CCTV by itself has become the equivalent of the honor code. It is so prevalent that people forget its there so many could be immune to it, or become immune to it if there is no repercussion after they have the first 'accidental' cheat. BUT I think that if the camera image could do something trivial (computer vision) in detecting (a) how many items the person pulled out of the cart and (b) how many items were left in the cart when they hit check-out, then just putting that number on the screen (e.g., "Your cart still has some items left" or "You removed 34 items from your cart and scanned 33 items. Please check for missing items") could be a deterrent too. And as for displaying actions to other shoppers -- that would be a privacy violation -- but if the "supervisor" (there is usually one at the self-checkouts) has a single dashboard with cam-views of all checkouts, and was alerted to behavior on any one of them, that would be within the purview of legal use by the store I think).
Sidenote: RE: the privacy debate around real-time media recording.
I actually had a discussion the other day about this w.r.t. Google Glass and how people are quick to pick on a single person as representative of their privacy concerns with video recording, but forget about the all-pervasive CCTV that does the exact same thing with much less awareness -- I'm calling it the 'identifiable perpertrator' syndrome :-)
Thanks for a great conversation :-)