Who walks around with $100 bills in their wallets for covering that next full tank refill? Lately I've resorted to stopping the pump at 1/2 tank. If everyone did it, "demand" would appear to drop in the short term.
Good point!  Luckily my Civic can still be filled for less than that :)

(I wonder for how much longer?)

Not really, unless by "short term" you mean "REALLY short term".  If everyone did this, you'd see a one-time drop in demand while we all lowered the amount of gas we drive around with, and then we'd all go right back to buying the same X gallons per week.
According to the "economists", if we punish the market by reducing our current demand, "the market" will quickly respond by lowering price to match the reduced demand.
(Tongue is in cheek here, of course.)
Yes, we "economists" do think that if you reduce demand (and beyond the extremely short-term blip that we were talking about re: not topping off gas tanks), then price will decline.  Economics, backed by empirical data in the form of a few bazillion data points, doesn't get much more basic than that.

Sorry if I'm being dense, but what's your point?  Why refer to reducing demand as "punish[ing] the market"?  That's an expression I've never heard before.

The "wisdom of the markets" says we humans should invest more and more of our finite resources into developing an "unsustainable economy". If I own a large oil field or two mega ones just for sake of argument, then it is in my Smithian short-term, self-interest (say I'm an 80 year old potentate) to use advertising of the mass deception kind in order to persuade others to buy SUV's and burn baby, burn that gasoline. Such activity increase the "Wealth of [my] Nation" and if Global Warming comes in a few years, who cares? I will have vanished before The Bottom hits. The markets always provide (... a final solution), ... err I mean Joy to the World, Joy to the Fishies in the Deep Blue sea, joy to you and me.