They didn't really "ban" anything. They just instructed the company that was hosting them to stop doing so, in the face of a media shitstorm. And since that company was also a licensee of the City, they saw it fit to do as told. A shop owner in the City can still do as they like.
[source: I was doing other work for the bin company (renew) and saw the whole car crash from the inside]
You are of course quite right. It wasn't a ban in any legal sense. Though I do think it highlights that the method is already frowned upon... and as and when the public becomes more aware of the fact they are walking around broadcasting their location there will be more pressure to restrict the collection of the data.
That said. CCTV does not appear to be going anywhere, and there is very little difference between processing video footage to track people and tracking a MAC address. The only difference in this particular case is that 'sharing' of the data between retailers is touted as a feature (which of course it is).
[source: I was doing other work for the bin company (renew) and saw the whole car crash from the inside]