Yes, well, that does seem to be the consensus, though you are the first to articulate sufficiently clearly to give it the force of a business rule.

ok - so we can see what you've written.

Could you drop me a note about the people you approached and their responses (or lack of response so far)? Alternatively, could you update the page at osm.wiki/Asking_users_to_accept_the_ODbL ? Thanks.