Yeah in my view a lot of the JOSM validator warnings are too strict.

For example source:geometry is fine and acceptable to use to document the source of the geometry https://wiki.openstreetmap.org/wiki/Key:source:geometry even on nodes. It doesn't need to be changed to source:position doing so has no benefit and just creates noise which makes it harder for mappers.

level=0 is a good way to tag something as being explicitly on level=0, otherwise you can't know if it wasn't mapped yet or really is on level 0. In fact for this reason alone I think we should/need to revert all these "Batch edit tags using JOSM validator" as it's damaging the data.

Furthermore can you explain your exact process for these changes? Because it appears like an automated edit, or are you manually reviewing and applying fixes. If an automated change it should be discussed first.
