Right...there are two different events. I imagine kids on that forum are talking of the one that is NOT for Tisch. Saturday (not Sunday) in the Square is Tisch's event.
I can give you a rough date of when that came out last year. I just know my D was lying in a hospital bed in traction awaiting surgery. Going by that recollection which is pretty vivid for me, the invitation had to have come around March 16-17. Her dad read her the mail over the phone when he got home from the hospital that night. I was in the hospital. It was very good medicine

. I believe not everyone who gets into Tisch will get that invitation and so even if you do not, you can still get into Tisch. However, if you do get an invitation, you are definitely accepted. The event is rather nice as well.
Fingers crossed to this year's hopefuls!!!!!!!!
Edit...my post cross posted with the ones above, sorry.