I agree with all that has been said and I wonder whether model engineer exhibition visitors at other European shows smell and behave in the same ways.
I do sympathise with the fellow in the wheelchair, I have read similar complaints before and I do try all the time to remember but stepping back is something one does after spending money, if only to get away from the purse moths. I can't see any end to this problem unless there is some sort of preferential wheelchair time allotted.
I would add some of the show people themselves who stand casually chatting for minutes, blocking the front of their stand, with their backs turned to people with questions or simply wanting to pay.
Don't get me started on lottery tickets in newsagents: the discussions, the fumbling to find the right change then dropping it in the choclate bars on the counter.
I have a feeling that we are describing most of the human race, present company excepted.