wiedehopf , where the fuel is coming from ? are you sure that all trucks are in perfect condition ?
never saw sparks at the exhaust on some loaders , tractors , etc ...?
oh thank you YouTube ahahah ...
"So any reason for leaving the fuel pumps off is more likely an overpressure / overflow / spill problem than anything else."
absolutely not Sir , simply as they are not required for refuelling ...
a lot of sparks are created in and around an Aircraft , thats the reason why , all AMMs have warnings at the beginning of the refuelling sections , normally , Nothing is allowed during refuelling except what is needed for the refuelling ...
"also what makes the time of refueling so much more dangerous than any other time?"
i am puzzled here ... i see you are in Germany , but for sure , not German , heard about safety first ?
Sir , thats the most Dangerous time when the Aircraft is on the ground for so obvious reasons ...