If I said it "will release" soon after D23 and it didn't, people would be pissed and say they were lied to. If I said "it won't release" people will be pissed, say KH3 is never coming out, and say that Square Enix and Disney suck.
I'm 99% certain this trailer will be available. It's at a public event where it's trailers will be shown on screens around the Square Enix section (as all previous KH trailers at JF have done). I just choose "should" incase Square/Disney went with that tiny slim chance that they don't actually release it, and thereafter this can be referred back to as "not actual confirmation, the hype wasn't entirely Chaser/Lunafreya's fault". If this is actually the case then I really do apologise to everyone for getting you excited for something that wasn't delivered.
I could have probably worded it better, with the word "might" perhaps, but that raises the chances that people would think it's not coming and be pissed because of that.
I'm sincerely apologise that this has caused you a bit of stress, especially with the resulting posts after your initial post.