Tagging certain features at 24/7 places, only available when full_service is provided

Every time passing 24/7 self service fuel stations, the SC question arises e.g. if compressed air is available. Yes, but only when the shop is manned, so the question is skipped. One shop keeper commented the tube w/ valve would be gone within the first day if he did leave it. So how to tag this? compressed_air=no compressed_air:conditional=yes @ (full_service hours), something along those lines?

(I’m pretty sure some other quest asked on another quest if only during service hours(?) but can’t remember which, to use the tagging as a lead).

I would simply create a specific object https://wiki.openstreetmap.org/wiki/Tag:amenity%3Dcompressed_air instead of using tagging that is very unlikely ever to be interpreted.