Right then, just to keep expectations in check, I asked the runner to keep left as I was going to pass on his right, I overtook at a speed which was marginally faster than he was running and at a distance which although was not massive, certainly gave him plenty room to flail arms and not be in any danger of hitting against me. If I was any good with GPX files I'm sure I could tell you exactly what speed I slowed to…my Forerunner 205 was recording...
Onyhoo I'm pretty sure my words were: "Hi Mate, passing on your right, please keep left, passing on right" as the last thing. Previously I'd called "Hi there"… no effect.It was slightly drafty (est 40mph windspeed, pretty average for Aberdeen) so I think that he probably was "in the zone" and the wind blocked his hearing from my earlier shouts, and just for the record I don't shout loudly at anyone as this is really annoying.
So, I thought that a bell might alert people politely that there is a slightly faster person coming up behind them to avoid the shock and holy crap moment this chap had.
I'm overwhelmingly nice to (almost) everyone, and don't seek to offend any road users or indeed pavement sharers. So, thread dwellers please bear that in mind.