Inertia
I feel like I could... TAKE ON THE WORLD!!
I tend to switch pretty quickly rather than rely on the other person to pick a side, otherwise it can get a bit uncomfortable as you both approach each other head on waiting for the other person to blink.Hm, it's another reason I don't like cycle paths, or perhaps a re-iteration of the one I sort of disagree with @mjr about in a thread that's now locked. Is it not the case that when two people are on a collision course what often happens is they both move to avoid each other ending up back on a collision course? And then do it again and even again? This is the 'shall we dance?' moment pedestrians sometimes have?
Thus if you stick rigidly to course you have a decent chance they move first or at least it's no worse than both moving, of course if neither moves, there's a short period where both work out the other isn't going to and then do so, trouble is, that's again often the same time frame, so you are back to square one. I've always assumed avoiding this situation is at least partly why there are pass this side rules in the first place.
This situation is so dangerous for aircraft that they have T-CAS (up to I think revision IV now) in airliners specifically to avoid it.
If I remember correctly this system negotiates with the other aircraft automatically and after a few microseconds of negotiation between computers advises one to 'pull up' and the other 'down' (there may also be some sideways component, I'm no authority on it).
I travel on the tow paths quite a lot in winter and theres usually at least one person I have to almost stop behind and shout at to get their attention. I could pass with room but Id like to at least know they are aware of me before I appear to the side of them.