Mature children should be treated as young adults and their privacy should be fully respected. Maturity here refers to mental maturity in which a grown-up child is able to discern between right and wrong. Most parents make a complete mess of the privacy of such children. They should not pry or spy on them and should even let them make mistakes. All that parents should do is to try to develop a strong friendly bond with them. This needs time, effort and dedication. By conversing with them about their fields of interest and indulging in small talk will greatly help. If such children are enamored by some teenage heroes, a particular sport, a television program or a movie, parents should try to become well-informed in these areas. This will provide them with a good topic for informal discussion with their grown-up children.
The purpose should be to develop such good friendship with these children that they start confiding in one of the parents. In fact, such should be the extent of this friendship that as soon as the child does something wrong, he or she comes to the parent(s) and tells them what happened. This is the target which parents should try to achieve instead of imposing restrictions on them. Parents should also remember that at best restrictions will only work at home. A child has to spend time in school and with friends. The moment he is free, he will break the shackles of these restrictions and perhaps react by going too far and cross limits.
Parents should also not be so ambitious as expect them to never or seldom commit mistakes. This is humanly impossible. They should remember that they themselves in their childhood made their share of mistakes. So why ask something of their children which they never complied with in their own childhood and which perhaps God too never has demanded?