As the video suggests, a call from your handphone can never cause an explosion at the pumps! The only reason why the petrol will ignite is when there is an electrostatic discharge between the driver who is charged and the car which is not and this is caused by getting in and out of the car repeatedly. The mobile phone has almost no chance, (and when I say almost that is 99.9%) that it can set off a fire. I don't know what made the government put up those stickers at every petrol station but it seems to me that such an event occurring because of a mobile phone is nearly impossible.
So the next time you get a call at the pumps, maybe just try touching the car as you get out (to discharge) or even better, just stay in the car and you'd be able to take that important call of yours.