I am guessing the reason is because Lucasfilm has recalled all prints of the original 1977 ANH and does not lend out the OOT anymore--only the SE prints may be screened. I remember a similar incident where a university wanted to screen the film as part of its 1970's cinema classics class and only were offered the 1997 SE. The OOT dies a little once more.
Zombie84 took this move by Lucas/McCallum and whoever as an attempt at further pushing aside the OOT. The logic was "If they don't have the guts to do a screening that doesn't have the OOT with L. Peterson's full magnitude of model work, then they are making a terrible choice."
I was only presenting the September OOT DVD release as the only available option if that is possibly going to be done. It's a stretch, as several of you have mentioned, because they are only on DVD and they would be using a normal DVD projector in a theatre. I agree with you fully on this. That is my point.
But many of you seem to think there is another option for them to choose. What else are they supposed to be screening that isn't the Special Editions? Those are the only apparent strips on a common theatre reel . . .Just like auraloffalwaffle said.