We had our Montreal interview today for EB1 & same thing happened as others have stated: that we were "refused" because there are no visas available until Oct 1st, but they kept our passports and said everything looked good.
One other hiccup was that they hadn't received our Immigration Medicals - even though we did them on Aug 27th at Dr. Lyndon Mascarenhas in Toronto. The Consulate officer said to just make sure they are sent before Oct 1st - she seemed surprisingly chill about it. I've followed up with Dr. Lyndon's office and that assure me they sent them in last week so I don't know how this is messed up, but I'll be chasing getting it rectified ASAP. Maybe a good reason to go to another immigration doctor than him as THIS IS THE WHOLE REASON HE EXISTS.
Otherwise, the process was okay. We had our 2.5 year old and they let us bring up her little backpack with some toys. We were shushed by security a couple times, which was, well, infuriating, but we got through it.