No company or government in the history of humanity has managed to foresee the myriad ways dishonest people will try to get away with dishonest things. Many, many, many, many, many companies have severely underestimated the high cost of fraud.
Also, employees trying to break the system are not likely to bringing young kids shopping with them.
The only question I have is who's liable when things are fuzzy: right now, the store bears the liability for things eaten within the store, destroyed while in the store, snuck out, etc. It's easy to see that this technology leads to the liability being pushed onto the shopper for all of those cases, but that will definitely lead to some serious customer-service arguments.