The Army Air Corps has operated light aircraft for some 70 years in densely populated training areas and close to the ground and I cannot remember a mid-air (though that's not to say there has never been the odd one).
A light aircraft is a 'seat of the pants and Mk1 eyball' machine with the emphasis on looking out of the cockpit not looking in. Light aircraft on training and air experience tend not to fly straight and level for very long so a good lookout is absolutely vital.
