Illicit Permitted, or Happy New Year Again

The marking of the lunar new year concludes today with the Lantern Festival, celebrating the brightness of the first full moon of the Year of the Rabbit. Chicago skies will be overcast tonight, so if you can't see the moon, a good second choice would be your favorite Chinese restaurant, right?
For some forbidden new year's aesthetic pleasure, check out the egoyomi - Japanese calendar prints - at the Art Institute through April 3. Why forbidden? See the AI page but the short answer is the 18th century shogunate permitted only a few publishers to print calendars. Educated elites illicitly commissioned their own woodblock prints to exchange with friends, requiring masters like Harunobu to furtively conceal the names of the months within the composition, for example, in the drapery folds of a courtesan's kimono.
Okay, you're thinking, this is the kind of infraction that's easily detected and prosecuted. Why did it go on? More generally, why do we so often allow things which we've specifically prohibited? The phenomenon extends well beyond parents of strong-willed toddlers. This week the New York Times recounts the withdrawal of a prohibitive NC-17 rating from the film "Blue Valentine" in favor of a more socially acceptable R, without any change in content. Daniel Pink, in the Wired magazine article Japan Ink, describes the flagrant copyright infringements tolerated by the manga publishing industry, where fans create and distribute their own derivative work. Maybe it was a little unfair and downright silly of the Tokugawa rulers to allow only a few publishers to control a monopoly on calendars, and perhaps they ultimately chose the wiser course by failing to enforce their own policy. The scholars and aesthetes who skirted the rules were playing a cultural game, not a political or financial one, so perhaps the stakes were perceived as sufficiently low. What can we learn and apply to other areas of our public and private lives? Is the first signal of an untenable policy its permitted subversion?