Our kids use Uber. They rarely and sporadically check ID for age. If/when they do, that Uber gets cancelled and they put in for another.
Our kids ride with day students if/when they choose. Connecticut doesn’t allow other teens in the car for the first year, but honestly…I just Googled that and never knew before (LOL!). We’ve told our kids who and what to look for when deciding to ride with someone. The whole reason we sent them to boarding school was to be independent and trust them to make decisions for themselves. We have never “said no” to driving requests, because we never required that they request and assumed that was well within the scope of what a boarding student can/should manage.