https://www.siliconvalley.com/2021/03/16/how-california-theme-parks-will-enforce-out-of-state-visitors-ban/

Disneyland, Universal and other theme parks in the state will hang “California Residents Only” signs outside their gates once they begin reopening in April after year-long coronavirus closures.

California theme parks will be required to limit ticket sales to in-state residents under revised state guidelines.