Imagine... you are flying at ~300 knots with about 3'-4' (sometimes closer) separation from the other aircraft in the formation.
In order to keep the stick from moving due to the bouncing from the turbulence created by the other aircraft, you have to brace it against your torso. You pull back, G-forces increase, and your suit suddenly puffs up.
This moves your arm... and the stick... to the side, which makes your aircraft move sideways... right into another aircraft.
It doesn't take much stick movement at those distances.
I can see exactly how a g-suit could be very dangerous for close-formation flying in high-performance aircraft.