Especially in the mountains, you often find informal spots suitable for pitching a tent, especially when somebody took care to built a stone wind barrier, something like this:
they should be only used together with tourism=camp_site .
The wiki also says it should only be used when itis legal to camp in such a spot, however, given my usage of OSM maps, that recommendation is in practice not heeded. I also think it goes against the verifiability principle - this is something that exists out there and the legality of its use can be specified with informal a access tags, no?
For a single tent pitch I would use tourism=camp_pitch rather than tourism=camp_site. The wiki suggests that a camp_pitch must be located within a camp_site, but actual usage doesn’t follow this rule. Tagging an informal backcountry camp pitch as a campsite (aka campground in American English) would misleadingly suggest it is a group of camp pitches clustered together rather than just a single one.
I have a followup question: There is almost a thousand backcountry=yes without tourism=camp_site, some seem to be clearly wrong, like benches in the middle of cities (people wanted to say they has a backrest or something?) or they seem to be indicating that a node is in the wilderness (like a gorge with the backcountry tag). Is it considered an ok practice to go through them one by one and where it clearly seems wrong, remove the tag (and where it is a campsite, add tourism=camp_site) even if I have never been there? Of course, if I would bein doubt, I would keep the things as they are.