RE: URI resolution & safety

This is an interesting discussion. I suggest that a
positive way of capturing the discussion is as proposed
revisions to RFC 2718, "Guidelines for new URL Schemes";
we should update RFC 2718 and publish the update as BCP.

In particular, while section 2.4 of RFC 2718 asks about
security considerations, it doesn't actually give very
many guidelines (such as "don't register URIs whose
security considerations are inadequately described").