User blog comment:Adzyn/Brave Frontier Starter Pack : Guide/@comment-24570336-20160101145020/@comment-24570336-20160102034733

I had a few times where I was joined by 1 or 2 Leechers in RC 5 Missions especially. I know you can't do RC 6 Missions without actually completing the Class Promotion Mission yourself. However, there is still the chance of losing, and losing in Raid cqn be a huge waste of time unlike most Quests.

There is also the option to set a Lv Requirement on your Missions. Leechers can benefit from those who don't set it and probably be joining 3 other Leechers together; otherwise, players that do set it may not encounter Leechers anymore. Well this can also be a Win-Win situation that I see fitting, but that is up to the players to decide.