That IS interesting about the breaking of IATA rules concerning denied boarding. I'm shocked when any airline rules are broken - they are there for the safety and well-being of the passenger - but in this case, perhaps not surprised. I am just so sorry for the inexperienced passenger who isn't aware of his/her rights. And you have raised concerns about luggage security. I can imagine British Air/Heathrow having a major conniption fit if they knew that unaccompanied luggage was being allowed on board. I hope someone looks into this aspect as well.
Mandi