"What if he had been walking and wanted to cross the road? Would he have had to wait until such time as there were no motor vehicles just in case one of them wanted to turn without indicating? Because that sort of thing happens very frequently. Is the pedestrian an idiot for trying to cross the road without waiting for all the motorists to drive away or come to a halt?"
Well when I'm crossing a road I stop at the side, check left and right, and cross when safe to do so (and probably wouldn't be doing so at a junction). In much the same way on a bike I'm looking ahead and left and right and judging when it is safe to undertake a particular manouevre, which wouldn't include passing a truck on the left just before a junction (whether indicating or not).
Maybe I'm more risk averse than most on here.