Nige,
'then surely it is a logical decision to cease AAR soties' - I agree completely. My point was that we shouldn't over-egg the issues by trying to compare apples and oranges - ie serviceability vs risk.
Having established that there is a failure mode that can occur in a system that was S when the ac took off, and that this failure mode is hazardous (production of fuel mist) in the presence of an ignition source, the options are - a) remove the possibility of the hazardous failure mode occuring or b) remove the source of ignition. As b is as yet unknown, a has to come first.
regards
sw