This is how i imagine it.
The more forward speed you generate (head wind) the less of an effect any rotor (side/up/down wind) would play on the wing (i imaging a speed boat cutting through waves, fluid dynamics and all that good stuff ), plus increasing internal air pressure of the wing making it a bit more "solid" yet "flexible" with the reflex wings.
there's plenty of other factors that would go into stability of the wing. The rotor acting like mini gusts on multiple areas of the wing, top surface mainly as wings get stability from pilot weight below it, not wind "weight" pushing above it causing poor control or a collapse. The less time spent in that the better. The wing quickly transitioning from one force to another spells trouble.
Would i have put my trims out ?
I would like to think i would but i bet i would of had to much to think about before thinking "trim adjustment specific to random landing spot with dead zone/rotor".
The pilot has had the time and experience to add those little extras on for added safety.
Best thing to do when starting out is don't use such areas as bail out zones. You want as little as possible that you have to think about when in these situations. At lest till experience dictates otherwise.