I have these two examples of stupid graffiti that I saw on the same day last week.
Exhibit A

Sighted at East Hills railway station (and not at an airport), this bit of graffiti suggests that my train is indeed a plane. FAIL.
Exhibit B

This graffiti sighted in the multi storey carpark at Lidcombee has to win the award for randomness. It says:
“Hope you have health insurance. You are gonna need it when I get finished with you”
And yes, mystery random graffitier, I do have health insurance!