Yeah, in my opinion @aighes and @Hungerburg nailed it above!
Like I said, methinks we should strongly advice people to tag ways that have the blue roundel traffic signs with highway=cycleway (and foot+bicycle=designated & segregated=yes/no depending on the specific traffic sign) instead of =path. Wikipedia may call them whatever, but local laws usually have more stringent meanings and precise nomenclature for explicitly traffic-signed ways. @_MisterY said that they have never been to a country that has those signs, but here in the North (I can only speak for Finland, Sweden and Estonia), they are ubiquitous.
Speaking more generally of traffic-signed pathways, in Finland, we also have very many ways with only “motor vehicles forbidden” traffic signs like this. Since the FtR laws here allow walking and bicycling almost everywhere, these form a widespread network very fittingly made for the highway=path tag (and, usually, would probably fit the path=maintained_way that @aighes proposed, or something along those lines). I’ve no idea how prevalent those traffic signs and such paths are around the world, though.
