> It’s hard to verify Summon is in use when only Tesla has access to the data
Mathematical certainty, or even criminal-style proof beyond a reasonable doubt isn't required. The insurance company writes the rule in their policy, refuses to pay if they think there is sufficient evidence that the policy allows it, and if the insured disagrees they get to sue the insurance company over it, and the case will be decided on the civil preponderance of the evidence standard.
Mathematical certainty, or even criminal-style proof beyond a reasonable doubt isn't required. The insurance company writes the rule in their policy, refuses to pay if they think there is sufficient evidence that the policy allows it, and if the insured disagrees they get to sue the insurance company over it, and the case will be decided on the civil preponderance of the evidence standard.