[xocnad]

But why would what parties take from what happened with Laconia be limited to the attacking craft being submarines? The exact same situation could have happened with attacking surface ships instead of U-boats. The takeaway seems to be that we can't trust our enemies not to attack us while performing rescues so we don't have to perform them.

San Remo which you referenced in another reply doesn't seem to go into what is required of combatants around rescues but it does say that rescuers can't be attacked [1]. That would make the Laconia argument be that I can't be committing a war crime by not rescuing survivors because I presume that I am at risk of having a war crime being committed against me.

[1] https://ihl-databases.icrc.org/en/ihl-treaties/san-remo-manu... : The following classes of enemy vessels are exempt from attack: ... and vessels engaged in relief actions and rescue operations;