Not a parent, but here's my perspective.
My mother always made me work for it. She had a door open policy among other things. She didn't actually care if I was doing the things I wasn't supposed to be doing, she just didn't want to find out. If she found out, it meant I was being too careless/stupid. It's actually a really good way to build up your risk evaluation skills! I did occasionally get myself in trouble (not with sex but other things), and she would help me out of the situation. Id get a lecture about what I did wrong afterwards, but honestly she was pretty good at teaching me.