Imagine this law was passed. Joe of Joe's Garage doesn't read BoingBoing and has no issues complying with the new law which obliges him to pass the security tapes he used to delete because they were so uninteresting to an agency representing SpouseTracker.com, and is not at all interested in revising his views of the necessity of collecting data of possible crimes against his business in the unlikely event he reads a paper about aggregating camera data to track individuals or an article about a stalker who tracked the target of their obsession using public feeds of nearby CCTV cameras, even if he makes the connection. The proprietors of SpouseTracker.com and stalkers everywhere thank the privacy advocates for their support.
"To prevent cities being turned into panopticons, we should make sharing data with people trying to build them mandatory"
The reason why panopticons work is because the prisoners don't know what the guards can see. And due to this asymmetric power relation, it is very hard to revolt. There are two solutions: either prevent the information gathering, or make the information publicly available. The former solution is not possible if you don't know what information is being gathered, so we are left with the second solution (to start with).
Back in the real world, I don't have any issues with the supermarket videoing me self-scanning, but would have issues with them being compelled to share information on my shopping habits in real time with literally anybody that wanted to know where I was and what I was doing right now and who I was with...