This was prompted by the appearance of rough plans of wild caves (eg Agen Allwedd) south west of Crickhowell [ https://www.openstreetmap.org/query?lat=1.55502&lon=110.34388#map=15/51.8316/-3.1823 ]. I suspect that they should not be shown, not least as they are not verifiable by 'an ordinary OSM user', but should anyway be distinguishable from surface paths or tracks. This test is for a verifiable cave accessible to all (at a price).