You know that whole emptying the tanks thing...didn't mythbusters do a test where they shot fuel tanks...it's the empty ones that are more explosive. But I think kerosene differs. Still makes sense not to have all that fuel though, lighter, less stress on landing, etc and less fire to cook you if the "landing" does go horribly wrong.
Yes near empty tanks are more likely to catch on fire than full ones. Reducing weight has more to do with stress on the landing gear than prepping for a crash.