I believe it does in practice, but I'm not sure about it being by regulation. I offer this from Transport Canada's Aeronautical Information Manual (pg 291):
9.25 Missed Approach Procedure While Visually Manoeuvring in the Vicinity of the Aerodrome
The pilot may have to conduct a missed approach after starting visual manoeuvres. There are no standard procedures in this situation. Thus, unless the pilot is familiar with the terrain, it is recommended that:
(a) a climb be initiated;
(b) the aircraft be turned towards the centre of the aerodrome; and
(c) the aircraft be established, as closely as possible, in the missed approach procedure published for the instrument approach procedure just completed.
With the runway in sight at circling the MDA, the pilot should execute the missed approach if there is any doubt that the ceiling and visibility are inadequate for manoeuvring safely to the point of touchdown.
I don't recall this topic being specifically taught in my training (30+ years ago now) and my experience with circling procedures is not extensive. When I started out, non-radar operations were much more common than today, so I consider a question like this in the context of "I can't see the aircraft so I have no idea where it really is". In that type of operation I would protect the airspace for the approach as cleared and that for the missed, approach as published. If the aircraft went lost comm, that is the only area I would "sterilize", unless it comes time to add for a possible diversion to an alternate airport.
If a pilot feels a missed is possible and that it would be advantageous to head back to the beginning fix or navaid, he should ask for it when the approach clearance is first issued. Unless there is some compelling reason, it will likely be approved. But in my view, he'd be on the hook for obstacle clearance though.
Dave in YZ