Boomerangben:
The point that I was trying to make was (a) see and avoid in general does not work well; (b) squawking makes you more visible both to radar units and to mini-TCAS devices -- both of these will give you a 'heads-up' on potential conflicts and increase the chance of see-and-avoid working. Hope this is now clearer.
QDMQDMQDM:
The advice from the military (when discussing the military low flying system at the CAA safety evenings) was to avoid the height band below 2000 feet and especially below 1000 feet. This was, I guess, to minimise the chance of conflict with low-flying military traffic, rather than other GA traffic.
AA.