Originally Posted by MattKing
What I meant, is that the question is made more complicated because it is harder to test whether the system is functioning properly.
If a wireless transmitter fires the flash at the wrong time with a focal plane shutter, the entire frame won't be illuminated - this is easy to see in a test exposure.
Whereas if a wireless transmitter fires the flash at the wrong time with a leaf shutter, the entire frame may very well be illuminated, but the exposure may be less, because of the shutter not being at its maximum opening. That is harder to verify in a test exposure.
Couldn't you do the white wall test? Shoot a white wall at a high speed (little ambient light) and see if there is light "fall off".
There won't be light fall off. The light transmitted by the leaf shutter will be even, it is just that due to the nature of a leaf shutter, it will perform in a manner similar to a second aperture. If the shutter isn't fully open when the flash fires, the shutter may effectively stop down the lens further than the set, normal aperture.