Originally Posted by CApreppie
I think US Customs expects people to answer "No." What Customs agents are trained to do is look for people who are lying when they say "no" by body language, speech, etc. Not sure what the punishment would be though if one asnwered yes or was found to be lying. Perhaps someone else can post that.
If someone has time for a baggage search or if he is sure one is imminent anyway, he should says, "Yes, I smoked a ton of trees on this trip; more in the week (or whatever) I was there than I ever have in the same time period anytime in my life. I know it's illegal here so don't worry, I didn't bring any back."