I don't know what italy and spain did, but when i say mostly voluntary, I really don't mean completely voluntary. the bay area has shut down bars and entertainment venues, and food service has no sit down service. Everything else has basically voluntary compliance - notwithstanding possible bad behaviors in neighborhoods I don't pass through anymore, there aren't cops going around arresting people for not obeying personal space distancing (though you could probably get in trouble, at least post facto via lawsuit, if someone found out your open air office was filled to the brim with employees).