The Lifeboat

[Bridge]

If all 100 people in the water are criminals it's highly plausible that the 50 people in boat is also criminals.

It also depends on what you define as a criminal. A criminal can either be a psychopathic killer, a file sharer, tax evader whatever. And how would you know if they were criminals? Would you question them 1 by 1 as they try to come aboard and ask them "Are you a criminal?" To which they would always answer "No." because they can either lie/tell the truth or drown.

All of them are murderers and can be easily identified as murderers, and all of the people on the boat are upstanding citizens. Would Batman let all of the murderers drown in order to save the lives of everyone on board? The blood is on his hands either way. The question, then, is: who should be allowed to live? The criminals or the upstanding citizens?