Those poor Palestinians

That's a Palestinian Authority garbage truck with a sign on the door that reads "In case of traffic violations, please contact The Palestinian Authority."
However what are those holes just peeking out at the bottom or the raised tipper bit? They are where Kasem rockets are fired from before the tipper part is lowered and the truck can be driven innocently away.
Any comments from the apologists for the Palestinians in the Liberal Democrats, Respect or similar?

Thanks to Theo Spark for the spot.