Guys your complaints are valid but you ate looking at the issue the wrong way.
You seem to want to punish these players rather then finding a solution that works for everyone.

I say add a button on the DF that reads "join only groups in progress". That way those people who want to queue for that are free to do so.

People queueing up normally won't notice them until someone disconnects in their party. Then this person who queued up progress will join your group and you will be happy you didn't have to wait, he will be happy he joined in progress, everybody happy!