I wasn’t asking about enforcement, all oneway footway restrictions I have seen were actually places where the restriction was punctually, not linear. I have yet to see a linear restriction, but I don’t question they do exist.
Just because of the nature of pedestrian traffic, it is much more unlikely that you may really only walk into one direction on a linear way (because as long as 2 persons pass, you can usually back up), while it is quite common to have punctual restrictions, e.g. on turn stiles, entrances and exits and similar.