Originally Posted by willy

I think you're setting yourself up for a lot of ass pain if you go this route. You're not breaking a lawful order, but at a minimum, you're going to elevate your name to the top or near the top of your PSG's shi+list - and that will be a lot worse than missing out on a day of free time.

Just be straight forward with your PSG and respectfully tell him you already had other plans for that day, and you'd really appreciate it if you could go ahead with your plans. And make sure you can clearly explain just what those plans are.

Whatever you do - do not take this above your PSG's head without first giving him/her a chance to reconsider. And if you've got an E-5 or E-6 between you and the PSG, it wouldn't be a bad idea to enlist his/her aid in this matter.