Sorry John - You may debate it all you want,but the fuel isn't coming out the vent on a hard pull up. BVM rumor only
The vapor is originating at the wing tip and I've see it with binoculars when you move the ailerons when the wing is loaded up.
If it was fuel it would happen on all days not just humid ones.

Sure is hard to get fuel to run against positive air pressure (about 10-20 lbs)
I've seen this plane since its very first flight and hundreds since then.
Hey, It did it before Tom put the external vents on.
When your the only one that has a plane that can do it ,I guess everyone has to make excuses.
I hate rumors,just face it, It's COOL!

MO