Only if those blackmailers have wrongly anticipated that their victims will be stupid enough to conform.

Not blackmailing in response to that anticipation is a property of the behavior of the blackmailers that seems to have been used in deciding to ignore all blackmail. Suppose there were lots of "stupid" blackmailers around that blackmailed everyone all day, even if no victim ever conformed. Would it be a good idea to ignore all blackmail in that case? Is there a distinction between such blackmailers and particularly unfair laws of physics (say, sadistic Lords of the Matrix)? (It seems plausible that there is no fundamental distinction, and sometimes the correct decision is to ignore these worlds, focusing on other possibilities instead, but that seems to require knowing that there are valuable other possibilities that would be hurt by permitting the assumption that you are on one of the bad worlds, and if you have good evidence that you are on one of the bad worlds, then rejecting that possibility means that you'd have to focus on very strange interpretations of that evidence that don't imply that you are on the bad worlds. This sort of rule seems to follow from deciding on a global strategy across possible worlds. It doesn't provide decisions that help on the bad words though, the decisions would only have a good effect across worlds.)

(I still don't have a good idea of what "blackmail" or "order-N considerations" means. Status quo (including the "default behavior", "do nothing", "not spending resources") seems like exactly the kind of thing that can be determined by decisions. You are only "expending resources" if you eventually lose, as the time at which resources are spent and gained seems irrelevant, so by that definition it seems that whether something is an instance of blackmail depends on whether it's successful. I suspect there is no simple rule for games, too many assumptions are potentially controllable by the opponent, and the only thing to do is to compare the consequences of alternative actions, and just act on that, which already potentially takes into account how the alternative actions would be taken into account by other agents, how the way in which they would be taken into account by some agents would influence the way in which the actions influence the decisions of other agents etc. Some sense of "no blackmail" may be a correct expectation about smart agents, but it doesn't necessarily suggest a good decision rule.)