50% is a red herring. They throw all sorts of BS into their emails to make the pilots think the individual reader is in a minority and in fact everything's going quite smoothly. Why else would they bother to quote the numbers... Apparently the real participation figure was <10% who wasted their personal time on the parallel bid.
I'm guessing some were new shiny joiners and the rest were the idle curious just off leave who'd had plenty of recent rest.
As always, simply more BS from the Crystal Phalace.