Hi,
Thanks for taking on this project!
How about this?
building=cabin
amenity=hunting_stand
hide=yes
shelter=yes
I wouldn’t use the tourism=* key for things that aren’t intended for tourism.
When I go hiking and get surprised by a thunder storm, it’s enough for me to look at the map and search for any building; no matter if it is meant for tourists. In an emergency like that you will be happy with anything, even if it is just under the canopy outside the building.
(Of course, you shouldn’t ever get surprised by a thunder storm when hiking, but we’ve all been there…) 