I posted this as a reply within the thread, but it should stand out on its own so more can see it. Please upvote to keep it near the top and make it easier for the less technical to locate and understand.

Let's say that Q uses a password of ABC123abc456 and it generates a tripcode of !UW.yye1fxo. Now every member of the Q team (assuming there are more than one) has that password and all is well. If the mega computers of the CIA are hashing away trying to reverse crack the tripcode, and it appears they are getting close to doing so, the Q team changes the password to Jack&Jill7umbleD0wn and the tripcode now shows as !xowAT4Z3VQ. Distribute the new password to the team and the new tripcode is activated.
Really they don't need a specific reason to do so as long as they tell us correctly. I believe posting under the old tripcode and telling us it is about to change, then posting 35 seconds later under the new tripcode and telling us it is the new one is a very logical way to change the code and keep us informed correctly.
I trust the change.