Oddly enough, we have advised against mapping exactly this kind of information in our Wiki years ago. Now I remember where I’ve seen it – Any tags you like - OpenStreetMap Wiki
What not to map
Entities in the OpenStreetMap database should relate to some geographical property or object with geographical qualities. For example, adding the location of a WLAN hotspot base station is considered acceptable, but tagging many nodes around it with the perceived signal levels is unwanted. Such information is better stored in a separate service.