This reminds me of when I was 17 and dating a girl who was 19. We were trespassing and getting busy on private property. In short we got caught by the Police and after checking our ID's they asked me if I was consenting to sex and if I needed any assistance. I found it pretty comical at the time.
When I was 17, I was also dating a girl who was 21. Not quite illegal, but 4 years is a pretty big difference. Maturity wise, she probably had at least 10 on me.

It's really tough to say where the age lines should be drawn, and how to prosecute the people that are right on the edges of them. For example, I wouldn't freak out if I heard a 15 year old freshman in high school was sleeping with an 18 or even 19 year old senior. Seems like half the freshmen girls in my high school dated seniors, and those guys could probably all be locked up for it.
Should they have been? I don't know. It would have made dating easier for me, that's for sure.
