The other thing the LEO could have done (DUH!) was put all three in the cruiser and haul them all in...
Or, escorted the 15yo to town, unless the "permit" that the kid had had a restriction about nighttime driving...
Anyway you look at it...this trooper had a brain-fart and it's stinking up the department.
Now, more training for those that already know better...and I'm sure some lawyer-type will require that stickers to warn any "newbies" on the force to "Think twice before acting once" are appropriately applied all over their crusiers' dashboards and in their lockers. Training films/DVDs will be made available for the additional instruction that will need to be done.