Well, Sugartastic, I was not previously aware of just how popular the Whitlow's half price burger night is. Who knew, but that's where the long lines were...45 minute wait, so I went in to Iota about 7:30 -- bar was virtually empty. I ate a not great burger at the bar and had a seat there until the Rosebuds came on.
But yes, you could have gotten stamped, left and come back. They don't start stamping until about 8:00, little after.