It happened to me too, on my fist test-ride after an 8 month rebuild from chasing it on my arse through a roundabout.
Turned left at an intersection and spun the rear.
"Sh1t, I've got a flat'!" thinks me.
Pulling over straight away, still idling, I look down and surprise myself at the Niagara of inflammable hydrocarbons bursting downward through the works.
Bike off (pump off) and the flow was under control again. Thankful the sparks were up the other end! Geez.
The belly pan did its job very well, holding about 5-6 litres before it began to spill into the rear track. Given the corners I'd just come through, I'm certain I would have crashed it again otherwise. I'm glad for my mate on his newly purchased FZ8 who was following too (!)
The new Dzus fasteners holding the pan on were a bit of a pain to get right the night before, and I wondered if I was being a bit pedantic. But I'm very glad I bothered, as I didn't have my screwdriver. Pan emptied (not on the road
I made it about 10k's and same again. The pan filled again in mere seconds. Pulled over again. Ok. This won't do. I needed something to stop it falling out again.
Then I see an old bloke watching me from yard.
A bit of tie-wire he did. And pliers. Champion!
With the lock wire around the pump-body and under the outlet, I finished the ride without a drip.
Given the way this has happened to others as well as me, and age on our bikes, and the potential for catastrophe... I'd urge everyone to do a quick lock-wire on the fuel tap outlet. It's only a 5 min job and could save your pride & joy, and more.

Lock-wire preventing the fuel tap outlet from falling out. When these let go, it dumps litres of fuel under the back tyre in a matter of seconds.