Jaba, surely the pilots of the brown one may be still inside? Bonanza drivers usually kit those aircraft out with all sorts of gizmos, so its reasonable to assume theres a bed, kitchenette and a TV in there, so they can stay for days.
The other explanation is that there were no humans around at all, and these two aircraft were indeed mating under the cover of darkness - until the OP turned on the floodlights and caught them in the act!
Flaps down - yes, they're caressing each other.
Cowl flaps open - yes, they're getting a little hot under the covers in their nocturnal activities.
Control locks removed - OK, so these particular Bonanzas arent into bondage..
Ailerons deflected - probably a surprised reaction to the lights suddenly coming on when they least expected it!