Yes. The internet is a dangerous place. If my children or college-age young adults are posting things they do not want a parent to see, then they are posting things they know their parents wouldn't approve of. For example, college kids commonly post sexually-charged photos of themselves (not necessarily nudity), pics of them downing liquor at keggers, that kind of thing. If I'm paying for my child's education, then underage drinking, smoking, snorting drugs and sex-kitten photos (or lists of conquests for males) are not what I'm expecting of them.
Also, look how many kids have been bullied or threatened via FB, and the parents were clueless until they found them hanging in the closet. Peer pressure of teens and early 20's is explosive, and too many kids feel that if they don't do what their friends do they'll be ostracized. Even good kids who've never been in trouble may do these things, and oblivious parents won't know until it catches up and they
do get into trouble. Then the parent looks shell-shocked and says, "But they've never been in trouble" because they ignored the warning signs until they were caught.
Uh-uh. The kids are good kids because their parents knew when to loosen the leash, and understood when to keep it taunt. When my children are out on their own, that's a whole different ballgame, but while my 18-21 yr old is in college, mommy is watching.