ive been caught several times. two or three times in high school, because that's when i smoked the most.
i got caught once after i was in college, it was when i was home for the summer. my parents dont really give a shit as long as i get it done in school, but my mom did tell me there would be SERIOUS consequences if they caught me again before i get a real job and stop living off of them. once im graduated and pay my own taxes, they said i can smoke as much as i want and they wont think any less of me.
they both smoke, by the way, just not that often. in that regard it's hard for them to say anything to me as long as im still getting good grades and maintaining ambition, because it would be fairly hypocritical on their part. they just dont want me to become a lazy pot head and burn out before i get a good job and live on my own. ive caught them red-handed twice though.
it just depends on your parents, dude. some people get lucky, like me, and some people have total assholes for parents.