When is an Antiquity Dealer a Collector?

David Gill ('Collector or dealer?' Looting matters, August 5th 2014) reflects on the question of the difference between antiquity collectors and antiquity dealers

So do dealers collect? Do collectors deal? How long do the "valued" objects remain in a collection before another "collector" is offered the opportunity to acquire them?

This is quite relevant to the issue of who groups like the ACCG and now ADCAEA are and whose interests they really represent.