People routinely take risks themselves they wouldn't impose on their kids.
It's much harder to believe that he didn't bring his son because of some weird insurance exclusion (presumably 1. they were insured for riders under 18 outside the vehicle and 2. he would have explicitly called out that it was a legal formality) than that this was extremely new technology which still had a reasonable chance of getting into a serious accident.
It's much harder to believe that he didn't bring his son because of some weird insurance exclusion (presumably 1. they were insured for riders under 18 outside the vehicle and 2. he would have explicitly called out that it was a legal formality) than that this was extremely new technology which still had a reasonable chance of getting into a serious accident.