@dalias @berdandy @mossmann I see. Yes, that makes sense for hospitals/ER.

Could they not however mandate them (or some other equivalent measures, for those with actual lung function issues) as part of "endangering others"? It is "proving a negative" difficult to prove that one isn't carrying some form of harmful unidentified biological agent, which in a place with vulnerable people means any potential carrier is a risk by default.