How do I give my kids some privacy, while making sure they're not doing anything illegal or dangerous?

My parents severely restricted my privacy when I was a teenager. Sometimes I would lock my room's door to prevent my younger brother from distracting me while I was studying, and he would tell father, who would then come and pound on my door until I opened to make sure I wasn't watching porn. I also found about my (safe and tame) fetish when I was a teenager, and parents soon figured it out so they tried to "shield me" from it, saying it was "wrong". I never talked to them about it, but it couldn't have been religious reasons because they're not religious.You can probably imagine how frustrating that was for someone who was still emotionally and sexually developing, and you can also guess that I don't want that kind of restrictions for my kids - I want to give them some privacy and freedom, but how do I make sure they're not doing anything dangerous? Is going through their stuff and computer bad, invasive parenting? What options are there?Thanks. via /r/Parenting http://ift.tt/2xAEVSH