Did same with my 3 girls only to find out the oldest had obeyed rules but once she was home & we were asleep, had climbed out her window & was off.
We never knew. Only found out many years later.
Seems that head-strong girls at that age can be damned head-strong.
That daughter is now a mom with 5 of her own :-) one coming up to same age she was when she did her exploring.
Doug M
(you have double my sympathy re being step da)