We've heard that in Italy there are fines and jail time ... but does that even pass constitutional muster here in terms of freedom of movement?
Generally, the fall under the state's police powers and the 10th Amendment. They have to be targeted at serving a legitimate state interest (stopping the spread of disease certainly qualifies), not be arbitrary, not have some equally effective alternative that doesn't burden civil rights, etc.
The legitimacy of the courts really took some big hits in the last few decades. Will the judicial branch even have the power to stop the other branches before this is all over? Only time will tell.
As for the shelter-in-place order, see:
California Health and Safety Code Sec. 120130
(d) The health officer may require strict or modified isolation, or quarantine, for any case of contagious, infectious, or communicable disease, when this action is necessary for the protection of the public health.
California Health and Safety Code Sec. 120295
Any person who violates Section 120130 or any section in Chapter 3 (commencing with Section 120175, but excluding Section 120195), is guilty of a misdemeanor, punishable by a fine of not less than fifty dollars ($50) nor more than one thousand dollars ($1,000), or by imprisonment for a term of not more than 90 days, or by both. He or she is guilty of a separate offense for each day that the violation continued.
https://medium.com/center-for-an-informed-public-at-uw/law-i...
[1] This is not about cops. https://en.wikipedia.org/wiki/Police_power_(United_States_co...
https://www.cdc.gov/quarantine/aboutlawsregulationsquarantin...
And that's back when things like Polio was raving populations, and could cripple you for life even if you made it through.
Point is, we've had to deal with this before... just not much recently.
I intend to break any sort of mandatory lockdown/curfew, without putting myself or anyone else at risk (e.x. going for a walk in a non-crowded outdoor area). I'm not comfortable with the government telling me when and where I can be on such a broad and open-ended basis.
To be clear, I'm not being reckless like people still going on vacations or eating at crowded Red Robins or whatever (https://brobible.com/culture/article/miss-nevada-katie-willi...). I've already been social distancing for a week and am now in full self-imposed lockdown (excluding mentioned outdoor walks and picking up essential supplies)
I just hope that whatever lockdown happens if it happens is sensible and reasonable as much as it can be.
Going for a walk in a non-crowded area is permitted under the order. See https://sf.gov/stay-home-except-essential-needs :
>It is OK to go outside for walks if you are not in a group.
If police stop people on the street and tell them to turn around and go home, habeas corpus might not be a particularly relevant remedy.
also, how does the conversation begin in the first place? do they pull you over under suspicion that you're not on your way to a grocery store, gas station, or friend/relative's house?
The order also allows going for walks as long as you're not with someone you aren't housed with, so the misdemeanor part is likely to be about gathering, not travelling.