@vbatts@fosstodon.org regarding the question of re-licensing, I was curious to see if OpenBeta's application of the CC0 license to content retrieved from MP was something the Creative Commons has had to address in the past.
Funny enough, I did find this in the FAQ, which seems to apply quite directly!:
May I apply a CC license to my work if it incorporates material used under fair use or another exception or limitation to copyright?
Yes, but it is important to prominently mark any third party material you incorporate into your work so reusers do not think the CC license applies to that material. The CC license only applies to the rights you have in the work. For example, if your CC-licensed slide deck includes a Flickr image you are using pursuant to fair use, make sure to identify that image as not being subject to the CC license. For more information about incorporating work owned by others, see our page about marking third party content. Read more considerations for licensors here.
So @viet, while I'm not a lawyer, perhaps if a route/climb contained material from MP, a declaration that xyz route contained material not subject to CC0 would need to be added.
That's made a great deal harder given that the data retrieved from MP might've been updated and changed in the meantime, so some thought would need to be put in to address how much of that original content is required in order to add the declaration.
