Oh, just had a thought. A less extreme yet quite related real world situation/question would be this: What is appropriate punishment for spammers?

Yes, I understand there're a few additional issues here, that would make it more analogous to, say, if the potential torturee was planning on deliberately causing all those people a DSE (Dust Speck Event)

But still, the spammer issue gives us a more concrete version, involving quantities that don't make our brains explode, so considering that may help work out the principles by which these sorts of questions can be dealt with.