I have watched two incidents of ASW15s ground effect flying across the
airfield with brakes shut and wheel going up and down. Quite amazing
performance!

An ASW15 pilot I once knew used to place a rubber band around the brake
handle. When he deployed the brake he thought "what's that rubber band
doing on the handle" and it reminded him to put the wheel down! A bit like
tying a knot in your tie.

I guess the converse is true. If it ain't got the rubber band on it then it
isn't the brake handle.