Fuel dumps tend to be in rather isolated areas, and airports
tend to have great empty tracts of land (something to do with
runways being long and narrow, and jet noise being hard to
concentrate beneath).

Furthermore, fuel pipelines tend to have automated systems
which recognize a breach and close valves automatically and
strategically. Heck, when you drive out of the filling station
with the hose still in your gas-tank, it breaks away nicely and
a check-valve stops the flow.

I believe various parties sensationalized the results for
interests of their own; the media because it's what they do,
law enforcement to reinforce their own importance in the scheme
of things and perhaps also to say "we missed 9/11, but see what
we prevented this time!"