I did have some doubts about that tag, but its wiki page describe it for **or elsewhere**: https://osm.org/wiki/Tag:amenity%3Dlounge

More importantly, the original proposal describes it as "a comfortable waiting/recreational area" for customers and **not limited to airports**, which doesn't appear in the current version of the wiki: https://wiki.openstreetmap.org/wiki/Proposal:Lounges
