David,
I still see this all as very vague. You say you will do whatever is reasonable to ensure maps have the proper permissions, etc., but this is unrigorous. Who decides what is reasonable? I also see a tendency to dismiss expressed concerns as unlikey edge cases, without any real facts behind it. To be fair, you could argue that the naysayers are not offering a lot of facts either. I admit my opinions are anecdotal based on my experiences (which are many), but they are certainly not irrelevent. Yes, you admittedly are for this (and your bias is evident), but what concerns me is the tendency to presume it is "okay" for a map to be posted unless proven otherwise. I am not looking for unreasonable burden on the overseers, but comments like
the maps with no owners are going to be the difficult ones since you can argue that no one technically has permission to post them but also no one has permission to say they should not be posted
seem cavalier. No, you don't have the resources to do exhaustive searches, but not sure what it means to say "No one has permission to say they should not be posted." In the publishing world, using the adage that it is better to ask forgiveness than permission is not a good guideline.
Scenarion: there is a map made by a dead guy that gets uploaded. the dead guy cannot give permission, but the poster was a good friend of his and assures you that this is fine. Maybe it is his kid and he inherited the map. (Yes, edge case). Now, let's say I know the owner and he has told me that he is uncomfortable with lots of visitors and would prefer to not have any publicity about his cave. Question. Do I have permission to have the map pulled?
The thread is going sideways -- everyone has opinions, and your clear bias is not furthering this. I recommend that someone (you) come up with clear guidelines as a proposal and let folks comment on that, and try to take a more balanced approach. In the end, whatever gets done needs to reflect the general will of the participants and adhere to a resonable level of responsibility. The latter is the crux now.