I have been told in the past that the tag virtual=yes was for routing purposes (if you can give me some time I might be able to pull the comment on a different changeset). There has been a long term disagreement on mapping pedestrian areas in the park with either ways connecting to points interest or using area=yes tags in defining the whole area. So I personally lean towards the area method but when I map new areas use highway=footway/pedestrian  ways to build the skeleton until I can nail down the landscape features and then draw an enclosed way with both the tags highway=pedestrian and area=yes to encompass the area. But in the past I have just turned the tags on the skeleton ways off with the idea that the future when the debate was settled I can retag them in whatever the new agreed format would be. I in the past few weeks have been called out by different moderator for forgetting to change blank ways to something as have ways in the system with no tags is considered improper. So about a year ago I was involved with another mod sweep and was told to set the ways to highway=footway and virtual=yes and I forgot to get around to it. So I finally fixed it against my better judgment. Personally I want to delete the ways but then you lose the ability to use navigation, so I am unsure how to proceed. 