I too thought the joining instructions would severely increase the chances of a mid-air but one doesn't like to say it because one gets branded a wimp
The other thing is that IMHO the vast majority of visitors do not fly in; they drive or get a train. Flying is actually really expensive
Another thing is that if no hard parking is available, most of the higher end of GA won't fly in anyway because they are likely to get stuck.
I assume the location was chosen because the organisers got a lower price deal?