Old Fezziwig
Thanks for the sour persimmons, cousin.
You have me mistaken, I'm not suggesting being gentle about it at all.Re the bolded:
What this would seem to prevent, or at least very strongly discourage, is the players in-character from distracting themselves with red herrings of their own invention.
Put another way, if the players have somehow convinced themselves that getting those Plans(TM) is the most important thing in the world right now even if in fact those plans are only tangential at best to their goals and thus the plans are a low-stakes thing, why not just let them play it out anyway even if it takes all night?
The bolded, as worded, almost seems to suggest gently leading them by the nose past the low-stakes stuff.

More seriously, if the players have convinced themselves such as you've described, we can play that, but I'm going to expect Beliefs to be written about the plans, and we're going to play a game about pursuing the wrong damn thing at the expense of what's really important, at least for a while (a session, more, whatever?). BW will stagnate entirely and the reward cycle will break down if players don't pursue their Beliefs, so we'd have to rewrite them.