Possibly, but not from leaving the engine running..altho something like this only normally happens in foreign countries. This is due to static exchange. Our pump handles have the "trigger hold open" device removed from them, so when you release the handle it switches off. Foreign countries in general (like US or Arab countries) have these still fitted.

This was investigated on mythbusters (just like the mobile phones myth, which isn't true btw) and this is how it went:

Users were getting out of their car and using the pump with handle held open (filling up). They then got in their car to get wallet/ purse, stepped out without earthing themselves on the car and then touching the pump handle. The static from them getting in and out of the car caused a spark which ignites the fuel vapours, boom.