I keep thinking magnets: If T foils pivot forward of mid-lift, with embedded permanent magnets holding the trailing edge up, then a kick-up at speed would overwhelm the magnets and disable the foil after a brief jolt.
Mechanically, it's a very simple release, requiring no moving parts. However, keeping them from locking down during a beach launch (where there's not enough speed to free them) might be problematic... unless one takes another crazy idea and glues an Alka-Seltzer in the way. :-P
--Glenn