Mine know, they aren't "cool" with it, but they're resigned to the fact that I'm an adult that can make his own desisions. When I lived at home I was caught about three times. One time with shrooms, and very surprisingly they were the least worried about that Well, now I'm in college, and the only thing they've said to me was:
mom: Are you doing anything illegal?
me:yeah, obviously
mom:I don't want you to get kicked out
me:I kept it a secret from you for years, I think I can handle it
mom:be careful

heh, oh the good old days of hiding my love for Mary Jane!