They sure are!
Yesterday we called in to a local service station to refuel Jim the Junior Jeep.
The price board said unleaded was $1.399/litre.
WHILE WE WERE FILLING the bloke came out with the numbers box and changed it to $1.599/litre!
A hike of 20¢/litre 
Fortunately, we were charged the price when we began filling: $1.399/l.
But what gets up my nose is that the petrol in his tanks was the stuff he'd had delivered at the lower wholesale price, whatever that was. He will be profiteering on the balance of the tank before he has to fork out for the next load at a higher wholesale price.
Time was (in NSW, at least) that the service station owners did not raise their retail price until the next delivery forced them to do so. Of course, this usually led to a rush at the pumps to get fuel at the lower price. I remember my father doing that.
Now, you can be ambushed by a price rise, without the justification of a higher cost to the s/stn owner.
End of rant.
Resume normal broadcast...
