Exclude dead PUGs as being part of your record that shows up when you're added up for PUGs. I know it's not the most urgent suggestion but it sucks to have a bunch of losses from PUGs that didn't even start.
Also, I'm not sure how the Halloween hats are saved (are they?) but when I rejoined after 2 months of inactivity, all of the hats I got during that event were gone.