Why is it that people take chances? Propane is highly flammable, it is heaver then air and collects at the lowest point, the more that collects the bigger the boom not that it matters at that point.
Not only for your sake but everyone else around you the tanks should be shut off before you pull up to the fuel pumps no matter if it is gasoline or diesel. One spark at the fuel pumps from a leaking propane tank and the entire gas station and the people around will disappear from the earth.
All you need is is static discharge from a cell phone around a leaky propane tank from your camper while pumping fuel and
I am sorry but I have a real problem when it comes to safety......cell phones is another issue at gas stations.