Oh no no no. This is not a good idea even to throw in the air. We should focus on implementing the planned Features for the consumer and Consumerium Services for more active participants and leave this kind of stuff to the technology consultant groups who are all busy trying to invent something to keep them busy in the eyes of their customers.
- That's why I put it on its own page. It's linked from visions and best cases now. Feel free to link it from worst cases and even threats with an explanation of how it could go wrong and discredit/disincentivize the whole system. Frankly I don't see any other way to actually know whether a user obeyed their own buying criteria, and the Ubiquitous case actually implies more privacy exposure by revealing whether someone bought something bad to everyone else.
We have more down to earth issues to deal with and besides my personal view is that paying with cash is nice. Maybe we just have to trust people that they "put their money where their mouth is" most of the time. Have you thought of this as an issue that could ruin the whole consumer privacy issue that is still a fundamental requirement for this to make any sense to a concerned individual who wants better knowledge of what every product has consumed.