So, my taking from this (for current situation, i.e. unless someone wishes to come up with new proposal):

  • tactile_paving=* should be marked on highway=steps way itself (and not on end nodes), and it is to be assumed that paving is only at top/bottom (and does not follow along the whole length of the steps, as that apparently doesn’t happen in real life)
  • if the tactile paving is only present on one side of the steps (most usually top of the steps, as it is the version that makes sense), it should be marked as tactile_paving=partial instead of tactile_paving=yes (which would be used if paving is present on both sides), and data consumer is to infer that.
  • in addition / alternatively, tactile_paving=incorrect might be used if tactile paving is only marked at the bottom (i.e. as wiki says “Where tactile paving is used but not in a sensible way”)

Would that make sense?