It seems to be unusual tagging that has no benefits over regular highway=footway but is confusing for data consumers and mappers.
Would it be fine to remotely retag it despite never visiting Ireland? Or would it be better to not touch it? Or wait for locals to do something with it?
Or Way: 25690641 | OpenStreetMap - this also has bicycle=dismount and segregated=no - I admit that I would be less sure what should be done here with this two extra tags.
I suppose if they were to be retagged, the ones that are sidewalks would ideally be tagged footway=sidewalk, and then the corresponding streets should be tagged e.g. sidewalk=separate. But as there are also examples that are not sidewalks, that would require carefully examining each case.
I assume that in most cases “bicycle=dismount” reflects the general prohibition against cycling on footpaths rather than specific signs, but again there might be exceptions.
Edited to add: looking at this again, the example I gave is not one of those with access=no, although it was mapped in the same area by apparently the same person. I don’t really understand if the “access=no” examples are different in some way.
Adding access=no to a highway=footway is really troll tagging for the renderer, as it leaves the footways available to routing software, but makes them hard to see on OSM-Carto tiles (pale grey dashes instead of red).
The “foot” profiles for alll three routers (Valhalla, Graphhopper, OSRM) route along “access=no” footways here:
I suppose routers look at the more specific “foot=” tag if it is available.
(This example also shows the different tagging used by the same mapper for apparently similar footways - compare the paths on opposite sides of Sylvan Drive. I don’t know if this tagging difference was intended to express some genuine difference on the ground).
any decent router will look at foot tag, my desire to edit this is not motivated by fixing routing as if it is not working then router is broken anyway
There are definitely locations in Ireland where there is signage telling cyclists to dismount. I believe the most known one is King Street South. The Irish cycling campaigns have generally been against them but councils continue to use them in limited locations. Mapping them is quite useful for being able to identify them and raise the matter.
Update: the layout of King St South may have changed so may not be a good example. The Shakey bridge in Cork seems to have a sign. Will try and get out to image/map it this week.