Well, if I had to think of a relatively negative context, my suspicion would be that these missions were more about relieving population stress on an island rat

Well, if I had to think of a relatively negative context, my suspicion would be that these missions were more about relieving population stress on an island rather than having a fair certainty that the mission would end in success. You send a party out, and if they make it - great. If they don't...well, at least your island has a little more living room now. Sort of like how medieval Europeans would have the firstborn inherit the kingdom, the second born maybe go into the church, and the rest maybe go crusading for glory in remote lands.