As a parent who is/was tired of her kids thinking they can do exactly what they like...let me set the record straight.........
No, the answer is not to let them get away with it and do exactly as they please while you sit there & take it, the answer is to find out wtf is wrong in the first place to make the kid want to rebel against you so badly, getting to know yourself and your children is nearly impossibly difficult but it can be done, taking a few steps back to assess the situation from an outside point of view can do wonders, backing off when you're not particuarly pleased with the path your child is going down is likely to make them come to you to seek approval, to find the answers from you! because you are the person they genuinely look up to!
A screaming, hysterical parent is not going to get anywhere with their kids, all that happens is the kid blocks it out *yer yer here we go again, yah yah yah yah, heard it all before, oh look my favourite Tv program is on, I'll chuck in a few nods and uh huh's just to shut this screaming banshee up!*
They aren't listening, they don't want to be told how much you dissaprove of them, how much you don't like them - they are teenagers, they are meant to grow and develop their own path, as long as they know you are there, that they can trust you to talk without getting a lecture, without the dreaded hysteria, they will come to you, they will discuss with you, debate, argue, but the end result is always the same, you give them the tools to decide which way they are going to go with it and they will use them, all the time with the knowledge that if they decide to take a dodghy path, they will face the consequences, not you, not anyone else, them! It's natural for any person who has had time to talk things out and weigh up the consequence to decide on what society calls the right path, yes, you'll get a few who will go hurling down dodgy street anyways, but those kids are going that way wether the issues are dealt with at home or in some program
Kids are sent away for stupid reasons, that cannot be denied, the programs themselves advertise that they can fix being Gay, ADHD, Depression .....oh please, come on, these are not fixable things, they are who the kid is, nothing will change that.