I'm not sure why you'd have to protect (or not protect) min days off. If you put all your vacation in one month, if you have been at the company for awhile, you'd have all days off. I would think the min days off question is irrelevant, though I have never done it.
Why would anyone want to put their vacation all in one month? So you have one month off and fly the rest of the year? That doesn't sound appealing.