With regard to the original question, yes, the Typhoon does dump fuel during its display. One of the best examples is the 'negative g outside turn' performed during the 2013 display routine (which is the best display yet and utterly spectacular by the way...) The dump vent is above the rudder so there is no mistaking it for vortices coming of other parts of the airframe, hope that helps!
-RP
p.s. I should add its a small amount of fuel vented in the grand scheme of things...
Last edited by Rhino power; 23rd Aug 2013 at 22:08.