I'll take my tongue out of my cheek........but even while I was writing it, the thought did occur that (a) it's not illegal to have fuel in an aircraft's fuel tank parked on an airfield and (b) it's not illegal to transfer some of it to another aircraft, provided that suitable methods to prevent and remove contamination are employed.
At least I hope it's not, because it's certainly something I've seen done (not by me, of course, Guv), although only between non-CAT GA aircraft, on muddy airstrips with no fuel at the bottom end of the airfield spectrum.
But the OP should listen to LME(GOD), not me. He is an IFQP Inspector, after all. (Yes, me neither,
here is the answer.)