Certainly most people are not dumb enough to just send weed through the mail without trying to mask the smell. So the question is, does the masking agent smell stronger than the weed? Well, as reported by The Belleville News-Democrat (Illinois):
Eight packages filled with marijuana were discovered at a mail sorting facility in Hazelwood, Mo. when workers there noticed the boxes smelled like pot.
Wait, you smelled the pot? But we masked that, dagnabbit!