infact the police advertised in our local paper a few months ago making a point of asking local residents to be vigilant about mobile phones while at petrol stations for this very reason. apparently there had been a spate of fires caused by mobiles being used at petrol stations.
they also warned of static electricity also causing fires at petrol pumps- and advised people to get out of the car completely, closing the door and not allowing anyone to get in or out of the car while its being refuelled- same thing, the static electricity causing a spark which when combined with fuel vapours ignites a fire.