Since crews can be opened/closed on the fly now, perhaps its time for being able to brig people in sloops? Only the player who has been in the session first/longest will have the option to help prevent it being abused.
I usually grind voyages solo while waiting for friends to get on and now that you can change crew type in game, sometimes I will open up crew to let randoms in and help speed things up. However trolls are aplenty, and currently on a sloop there is no way to really stop someone from trying to sabotage your boat/loot/supplies you have worked so hard to accrue.