"A member has withdrawn from the duty."

[Bankai305]

Nope.

The whole purpose of the join-in-progress feature, is to make sure there are replacements for when people leave a dungeon mid-way. Why it was put up as a separate option, was also very simple: because a lot of people prefer to do full dungeons.

So in order to make everyone happy, join-in-progress was made as an option.

The purpose was never to make sure new people can get in-progress parties. It was to make sure already in-progress parties can get replacements.

The option, in full, would read: "I don't mind joining a dungeon in progress".

There's people who prefer, and ONLY want to join instances in progress, which is why we currently have this problem, and this threat exists. So the option should still be there, for the purpose you just mentioned, but they need to make people who queue for in progress content separate from people who join for brand new content. So those who wish to join a dungeon from the beginning do not have to deal with people who only want to join dungeons in progress