AQ has almost always had options to limit who can see your boxes, but to limit access to all of one's boxes could be a serious chore if you had a lot of boxes planted. No more! The box lock page allows you to set P and F-count restrictions on all of your boxes at once. You can set a minimum restriction, or you can increment existing restrictions by a certain number. (You can also set maximum restrictions, and decrease existing restrictions when you feel it's safe to allow more access to your boxes.)
You can also change specific types of boxes. For instance, you might want to restrict your traditional plants, but you don't need to restrict your personal travelers. Assuming most people are interested in adjusting the settings for traditional boxes, that's the default box type that will be affected, but it's possible to adjust any of the box types--or all of them at once.
But.... here's hoping you'll never have any use for this feature! *cheers* =)
-- Ryan