Just went to the website.....
I think its hilarious! Totally tongue and cheek.
If people have a problem with this they need to get a sense of humour!
Having said that though, I can see why Jetstar pulled out, and I would not have been impressed with having to work on that yellow painted 717.
With "Get on, get off!" written down the side of it, i think it would give permission for pax to behave very badly. And I wouldn't want to be a "mostess" on that plane!