kevin, you need to stop trying to shelter your children and start educating your children how to protect themselves.
removing choices from them is not a good way. they aren't babies any more, they have the capacity to understand, it is up to you to find a good viable way to teach and show them the choices and the consequences for those choices.
i have found when i remove freedom it only spurns rebellion and deliberate willful disregard into reckless abandonment into what ever it is you are choosing to deprive them off.
kids are alot smarter than you think, you just have to recognize which level they are at and present things to them in a way they can understand that is reasonable.
even if you think your child is bad alot of times they do it just to prove to you they can do it, not because they want to do it. you'll be surprised at the good choices your kids will make if you give them the opportunity after telling/showing them the real life consequences and quit sheltering them.
when your children have demonstrated their good decision making enough you can just give them free will as long as they follow a set of working and reasonable parameters to stay within the guildlines.
yes they are going to break the rules and push the boundaries. yes, expect them to do so. mistakes will be made, sometimes it's the only way people can/will learn and grow from them.
tell them what your response will be ahead of time and why.
a HUGE part of why children don't tell their parents about the mistakes or naughtiness they do is out of fear of what you will do if left to their own imaginations and knowing what you WILL do is enough to keep them from doing it provided you follow thru with the action you stated. as long as you promise them to help them and be reasonable/appropriate, they will be more forthright with you.
it is better to have your children more prepared should you drop dead of a heart attack tomorrow and will save you more peace of mind knowing they are ready and able to handle ALL of lifes challenges on their own.
now, if you happen to have that bad apple or want to put the fear of god into them, seek out people who have made those bad mistakes and learned from it, and ask them to tell your children about it and show your children what will happen to them should they choose to continue with their behavior. i have found the internet is a great tool for showing children what each kind of behavior gets you from people all over the world and how fortunate they are not to have to learn it the hard way for themselves today.
the nazi approach to removing choice from them is best saved for prisons as a weapon of last resort lest they become too acclimated to such freedomless life. children do figure out pretty quick when you have nothing left to lose there is very little reason not to risk doing something.
generally a child will let you know when they are ready to handle more by fighting you for greater freedoms or trying to circumvent activities around you or without your knowledge.
key logger or web history snoopers are great for finding that out unless your one of those parents who never notices when things are going to well and too quiet for too long.
as far as porn and booze go, the less you know the more you're curiosity will thirst for it, the more acclimated to something, the less likely and infrequently you are to make wild, brash, stupid decisions that lead to big mistakes from what i have observed of people from all over the world and how they grew up.
i'm much more inclined to let a child learn what ever they want to know about sex online and loosely supervised than on their own in a bed with some one, and if online 'entertainment' keeps them from the up close and in person for as long as possible before becoming a grand parents or std's and other diseases being spread i'd be happier to be less worried and paranoid of the things we did when we were teens.
my road of life was less bumpy than most. i and others have attributed that to friends/family/people we knew that had things worse and were sign posts on the road of life as to what not to do and what to do.
i had a parent who did this for me while the other parent was always a nazi i understood and frequnetly disobeyed because they were always trying to tell me i could not do anything rather than teaching me wether or not i could do a thing and why i should or should not do such a thing. if you want your kid to be a dumb little drone that does as they are told, be the nazi control freak, your child will be less likely to ever be able to live with out dependence on you to do anything into their adult life.
if you want your child to do great things, and not need you to pave their way thru life, let them learn even if you can see they are going to make mistakes, teach them, not control them and they will be able to think and act for themselves. all you have to do is observe and encourage them to try and be ready to catch them when they fall/fail. children and adults love you more for that. it is so very hard to do, just keep in mind if you don't let them, you will always have to take care of them that much more for so much longer and probably in a very unsafe way on their own with out you and you'll find it gets a little bit more off that great weight on your mind.
that and sometimes it can be hilariously funny how well they learn more often than the frighteningly scary. but the frighteningly scary is what you want THEM, to want YOU around for.