Here I am trying to investigate the effects of side wind on a full fairing.
A standard motorcycle and rider will have a CG in the gas tank and above the
CoP so an aero induced torque will likely help the tendency to lean.
On a scooter the CG is lower and further aft. If the CoP is above the CG, the induced aero torque will tend to resist a lean into the wind. These forces and dimensions could be adjusted to complement to the over all handling of the machine.
What I find on a bicycle is that frontal profile is like an ice cream cone, round at the top and tapers to the bottom. By making the air going under the bike to move faster some reduction in lift can be generated. A big difference between a bicycle and a motorcycle is the ground clearance. For my bike fairings I stop just below the knee and have 20 inches clearance. A motorcycle may have 4-5 inches clearance.