It's simple. It was technically voluntary, but with all of these bulletins and the media saying to shelter in place (not a hint of "if you really want to" to be found), most people got the distinct impression it was mandatory.
Those who went out in it met with very mixed results.
The language throughout the press conferences was mixed, and the language was certainly stronger when it came to businesses. People's lives were screwed by this. Some medical treatments are timed, and very important. Some people live paycheck to paycheck and get paid hourly --- do you think they'll be compensated for not being able to work? Some folks probably did not have a store of food in their homes. There was really no warning for this, but then they were shut in their homes "voluntarily" unless of course the police came to their door and asked them to evacuate.
Somehow that doesn't seem right or necessary, as dozens have said in this thread alone, but now we are just chasing our tails.
This is what someone else said in another thread:
"It would seem to me that the reason to have a curfew in this particular instance (where a crazed gun-firing, bomb-throwing criminal is involved who may be strapped with explosives) is not so much to catch him per se but to prevent a mass casualty scenario. At least that is how I understand it with the very limited emergency disaster training I have. Thus, airports were closed not because he might get on a plane, but so that he doesn't blow himself and several dozen other people up with him in the airport.."