Many states (for example, Washington) around the US have issued an executive order prohibiting their residents from interacting with other citizens face-to-face, unless its a part of an "essential" activity:
All people in Washington State shall immediately cease participating in all public and private gatherings and multi-person activities for social, spiritual and recreational purposes, regardless of the number of people involved, except as specifically identified herein. Such activity includes, but is not limited to, community, civic, public, leisure, faith-based, or sporting events; parades; concerts; festivals; conventions; fundraisers; and similar activities. This prohibition also applies to planned wedding and funeral events. This prohibition shall remain in effect until midnight on April 6, 2020, unless extended beyond that date.
Is there precedent in US law for such a restriction? Or perhaps someone already tried to challenge this rule during the current pandemic? Preventing citizens from going to each others home for a visit seems like the ultimate form of restrictions, so it would be interesting to see if it ever held up in court.