[coryreu]

Jeremy, all you simply need to do is state the obvious and say you're not going to be at the meeting.
Giving yourself, and anyone else who is willing to listen, reasons not to go to the meeting is smart on your part. Examples: "Shouldn't because it's 2 days before the Jam this Saturday." "Shouldn't because it's a waste of gas and you should see my work before you speak." "Can't because there was no notice." Whatever your reasons, it can't discredit the purpose of the meeting.
I'd do the same, if I thought there was no chance to win a debate for approval prior to your project.
Why not attend the meeting and see if you can receive approval through legitimate means? It can't hurt, can it?