Ya, I think there's a difference between your parents telling you when you can or can't date, or merely giving you advise. When I was like 14, this girl and I started hanging out a lot, and eventually decided to start 'dating'.
My parents, of course, didn't approve... mostly because the fact that I was 'dating' at 14 was ridiculous. My dad threatened to 'talk to her parents'. I'm pretty sure I threw a temper tantrum and became all depressed.. and eventually my parents just decided to leave it alone. Later, of course, she 'dumped' me, and I get the privilege of looking back at that year as one of the most ridiculous times of my life.
So sure, my parents didn't approve, but for them to say that I had to stop seeing this girl wouldn't have worked... I was completely lost in the feelings of being in a relationship, and if they decided to lock me in my room or whatever I would have rebelled and probably done some REALLY stupid things.
Their best course of action really was to just let it play out, and let me learn from my own experience. Which I did.
If you've ever been captured by those emotional feelings, you know full well that you're probably going to ignore anything your parents say, because you're blinded to anything else. So for them to take forceful measures wouldn't help anything. The best thing they can do is keep giving you advise, and after it all wears off you can thank them, because of course they were right.