In New York City, beginning on Sept. 13, anyone over the age of 12 won't be allowed to enter "certain covered premises" inside the city -- including Barclays Center, home of the Nets, Madison Square Garden, home of the Knicks, as well as any other indoor gym or fitness setting -- without providing proof of at least one dose of the COVID-19 vaccine, unless there is an approved medical or religious exemption for them not doing so.
In San Francisco, beginning Oct. 13, everyone over the age of 12 must show proof of being fully vaccinated before entering any large-scale event -- including NBA games at Chase Center -- as well as any indoor gyms or other fitness facilities, again unless there is an approved medical or religious exemption for them not doing so.
These laws apply only to players on the Knicks, Nets and Warriors, and not to members of visiting teams coming to play those teams. The reason for that is the laws in both New York City and San Francisco have exemptions for out-of-town teams coming to those cities to play games. Those exemptions, however, do not exist for the home teams in those cities.