I never use cooking spray, but ran across this post on the Freakonomics site, and pass it along without verification:

"My favorite is how cooking spray will always say “Fat Free”, when it’s essentially a can of pure fat. It turns out you can list 0g of fat if your serving size makes the fat turn out to be less than 1g.

What is the serving size? 1/3 seconds of spray (or .226g). I want to see someone try to cook their eggs with that little oil in the pan."  (posted by dickgrogan on Jan 4 under the Freakshots topic of the same date)