Hi,
https://wiki.openstreetmap.org/wiki/Key:quiet_hours
https://taginfo.openstreetmap.org/keys/quiet_hours#overview
The quiet_hours proposal is only used in 12 places worldwide, this is far from wide use. The sign on the front door specifies sensory, not just quiet, which includes visual and auditory stimulation reductions. Quiet implies only auditory reductions. Walmart as a whole has started to implement this at least on the regional level but I imagine on the national level as well, so the opening_hours:sensory=* tag makes the most sense here.