Bill Dunphy says:
I came across this post "Burger King has a bad taste …." on Digital Frog, a dutch photographer's blog. It's a photo he says of a tray liner his son got in an Amersterdam Burger King.
The trayliner depicts the airport-style high security Burger King uses to ensure that only the top ingredients are used. Images include a scared Onion with his trousers down around his ankles while a fierce-looking Pickle guard with a latex glove, prepares to digitally examine him! Scattered about him from his open luggage are veggie porn mags!
I left a comment for the blogger asking for more details and suggesting it was a spoof or a prank and he linked to an advertising site which appears to validate his claim that the tray liner is real:
Hi Bill !
Sadly, this was not a joke. Burger King really served my son with that paper on his tray. This was early may 2008 near Amsterdam (NL).
I found another reference of this here.