Kayak example: https://omaps.app/w4CNuytXo0/Hôtel_des_Marronniers a random hotel in Paris. The big K icon labeled "photos, reviews, booking" or something like that.
As for TetheredNet, it's for a different reason. It's not that it's tethered to OSM, it's that it's tethered to Organic Maps's servers serving pre-processed maps. (Organic Maps can't fetch data from OSM directly)
It's not deliberate. What is their motivation for doing that?