Normative Signs: The Poetry of "Ought"

My pal Jim sent this one, taken in a hotel room (in Luxembourg). It’s an ashtray with a “no smoking” sign in it.

Is this a mixed message? A form of tacit permission to break official rules? A way of taunting the addict? Or (more likely, I think) a way of catching smokers’ attention, by putting the ‘no smoking’ sign in the one place that every smoker is bound to look?