Not carrying ID can actually get you into trouble in California when performing some activities that don't even require a license. See for example this interes

Not carrying ID can actually get you into trouble in California when performing some activities that don't even require a license. See for example this interesting discussion on someone who was pulled over by the police, while bicycling and not carrying ID: https://www.bicyclelaw.com/do-cyclists-need-to-show-a-drivers-license-if-they-are-stopped-by-police-in-california/#:~:text=The%20law%20is%20very%20clear,license%20to%20ride%20a%20bike.&text=It%20only%20means%20that%20if,with%2C%20you%20can%20be%20ticketed https://www.bicyclelaw.com/do-cyclists-need-to-show-a-driver.... The Court also concluded that while McKay had verbally identified himself, the officer has the discretion whether to accept the verbal identification, and noted “Here, of course, defendant was not arrested merely because he failed to produce a license. He was arrested because he violated the Vehicle Code. At that point, the need to obtain reliable evidence of identification and ensure compliance with a promise to appear is equally great for a bicyclist as for a driver of a motorized vehicle. Although only the latter is obligated to have a license in his or her possession at all times while driving on the road (§ 12951, subd. (a)), both are required to produce satisfactory evidence of identity for examination when stopped for a violation of the law.” McKay, 625.