Well, this isn't a legal advice site, so you would have to take that up with with your attorney.
However, from a semantics viewpoint, one can take this to mean a few things.
It can mean that a dog that is actively hunting (as oppossed to just being a breed that is some type of hunting dog) doesn't need the collar/harness, but must wear them when they are not actively hunting.
I don't think it means that.
Or, and this is my take on it FWIW, that what is being discussed is the valid license, not the collar/harness.
Meaning they must wear a collar/harness, but it doesn't need to have the valid license attached. Maybe because it makes noise?
When you refer to "the tag", are you meaning the valid license? If that's the case, that's what the City Prosecutor said.
In any event, for the dogs sake, they should always wear a collar/harness, and be microchipped.