I was in Melbourne last week and noticed the method in use to mark the area of a footpath approved for outdoor dining. Small disks are inlaid or stuck to the paving every metre or so in a line, delineating the approved area.
We have had some problems with footpath dining in the City of Ryde where tables and chairs have encroached onto the passageway interfering with pedestrian progress. If the problem continues the Melbourne method may be worth a try.
