What if a kid whose parents doesn’t own a car (or have insurance) drives someone elses car and gets into an accident?
It depends. If the owner has insurance and the child who is not a “Family member” has reasonable belief that the named insured would allow the insured to drive it (for example, a nephew who is in for the weekend), then they would be covered under the auto. However, if there is no “reasonable belief” (for example, a frat buddy (or yeshiva bochur) “borrowing” the auto of a student who is insured under his/her parents’ policy), then they could be denied coverage. They may still be covered for liability up to the state’s FR limits (depending on the state and court. See Progressive Northern Insurance Company v. Concord General Mutual Insurance Company as an example of the complexity). I do not know if they could be arrested for driving without insurance, but I doubt it.
(once again, this is not a legal opinion).