OP is certainly right that a lot of this legislation is written in ways that are hard to interpret and that often seem like they would have undesirable side effects even under the assumption that the basic idea is good (whether that's actually true is a whole different question).
In the specific case of CA AB1043: (1) Systems are required to ask the user for their age and just trust whatever they say (2) Applications are required to query the system for the user's age range. Other enacted and proposed device-based age assurance mandates have different properties.
In the specific case of CA AB1043: (1) Systems are required to ask the user for their age and just trust whatever they say (2) Applications are required to query the system for the user's age range. Other enacted and proposed device-based age assurance mandates have different properties.
This post goes into quite a bit of detail about the various points of concern: https://educatedguesswork.org/posts/device-based-age-assuran...