Today, when queued for an ops group, someone kept declining the queue and rejoining immediately. That prevented 7 other people from playing, and also rapidly flashed the accept/decline window, which was very jarring. It was done too quickly to see who wasn't accepting. If you could lock someone out when they decline an invite, even for a couple of minutes, it would get rid of this problem.
Also, when asked to move this thread over to suggestions, I was shocked that the forum wasn't just a dead drop