I had a hard time with this kind of situation as a kid myself. I HATED being a minor. From day one I wanted to be able to do everything an adult could do and I resented that I wasn't given that kind of power.There are certain activities that we do not deem kids ready for, but which we regard to be OK for adults. Driving, drinking alcohol, watching hardcore porn, etc. This does not make us hypocrites. I also expect to be able to supervise my son's activities on the Internet, but I don't expect him to supervise mine. Is this also a "double standard"?
I think what would be most effective in working with kids that have the same attitude I used to hold is to make them understand that other than "protection" of them, it is more about them needing to accept that only experience gives you wisdom, and many choices that involve intense subjects like sexuality, alcohol and other adult oriented pursuits have to be reaonably restricted so they can learn before they make any IRREVERSIBLE mistakes. A good way to start is to tell them that you don't know everything, but when I was your age I did. If you can sink that mindset into them to realize how thoughtless and uniformed you are in your early years, you might begin to have them understand why it's necessary.
There is as Mike says though a line drawn as well. You cannot be a smoker and then jump on your kid about it. That is truly being hypocritical from a moral standpoint. Some things you really DO have to demonstrate or you lose your credibility.
But when it comes to things you actually own as possessions as an adult citizen that pays taxes and puts a roof over people's heads? Hey, the adult has to have SOME benefits for being the responsible provider. One of those is the right to choose their own recreational time and juggle it accordingly. Children of same do not actually "own" certain things in the household, and so it's purely out of good will to let them use the parents possessions.
They may not like it, but then their only other option is leave the house, get a job and 'discover' the real world and how much fun it is to make ends meet.