Definition: A small, rentable building or shelter (or a group of such structures) with limited amenities, designed for short-term lodging in natural settings. Most often a single unit.
https://wiki.openstreetmap.org/wiki/Proposal:Key:tourism%3Dcamp_lodging
Please discuss this proposal on its Wiki Talk page.
An example picture on the Wiki page would be helpful 
As with tourism=chalet, this tag may be used to represent either a single structure or a group of structures.
I would skip this ambiguity and provide a clear tagging guideline for groups of buildings instead. Otherwise data users will have no idea if the tag means “single camp lodging” or “area of multiple camp lodgings.”
I’ve just added some examples with images, thanks.
provide a clear tagging guideline for groups of buildings
Are you aware of an established precedent for this sort of thing?
Yes:
I would personally prefer to use tourism=camp_lodging like tourism=camp_site, because with that method we can use (a lodging equivalent of) capacity:persons=* / capacity:cabins=* to indicate the number of camp lodgings inside a camp lodging area.
Coming to think of it, why do we even need tourism=camp_lodging in the first place when we can already use tourism=camp_site + capacity:cabins=*?
Indeed. We already have this challenge with tourism=chalet - Elsewhere I previously wrote about the rigmarole I had to go through to process the data. To have one OSM tag like that is unfortunate; to manually propose a new one like that seems - not a good idea.
Suppose someone buys a glamping pod like these and puts it in their garden, or a handful in a field like this:
Is that a tourism=camp_site? The Wiki page says:
Note that while camp sites might (or might not) include occasional building=cabin or other housing accommodation, those are neither required nor indicative of tourism=camp_site (which is defined by having pitches for placing tents and/or caravans/RVs
But I don’t know if that’s just someone’s opinion or actual tagging practice. I’ve checked one example of a glamping site that I am familiar with and it is tagged as a camp_site, despite not having anywhere to pitch a tent.
Coming to think of it, why do we even need tourism=camp_lodging in the first place when we can already use tourism=camp_site + capacity:cabins=*?
It’s the same reason we have tourism=camp_pitch when we already have tourism=camp_site + capacity:pitches=*.
camp_lodging is analogous to camp_pitch. It’s a unit within a larger site. camp_pitch is an empty space for erecting one’s own lodging, whereas camp_lodging represents a space with dedicated lodging.
to manually propose a new one like that seems - not a good idea
I understand the concern and have struck that from the proposal.
Suppose someone buys a glamping pod like these and puts it in their garden, or a handful in a field like this
If there’s just one in a private garden, you’d map it using just the relevant building tag and no tourism tag. If there are multiple, and they are for renting, it does start to become a bit more ambiguous. My personal feeling is that that guideline from the wiki is a bit too heavy-handed. But there’s also always leisure=resort if it has more that feel.
If we feel that “camp” is too specific, we could certainly genericize to something like nature_shelter, lodging_unit, natural_lodging. The reason I went with “camp” is that is makes it similar to camp_pitch, but I’m certainly open to discussion on this.
For a different argument, it’s not the same, when this has building= already. Why do you need another tourism= feature inside a =camp_site then? I suggest using an attribute with the building= , to avoid the single vs group problem . Proposal talk:Key:tourism=camp lodging - OpenStreetMap Wiki