Yeah, what Alhanelem suggested (have "Join in Progress" only work for in-progress parties) is a good idea but has the flaws you just mentioned above. I still believe hiding the progress and making the pop up just let you know it found a party for you is the best way to go. Once you get in you'll see what you got, and if you decide to eat the half an hour punishment, your problem. I still don't think the problem will ever go away completely, but it will for sure reduce the drops by a large percentage.