If Sept 26/27 arrives and Resverlogix attends, then any discussion of notification for a cancelation is moot. But if for any reason (scheduling conflict or otherwise) they don't attend....I don't see how Clayton or anyone else could claim that their attendance hasn't had wide distribution....when you put something up on the World Wide Web things snowball.
Did a search on Twitter for Resverlogix and there's a poster (a graphic that looks like a poster in any case) which says:

Its been tweeted and retweeted by numerous accounts, including my own.
FancyFinancy with over 5,900 followers
Zack Capp over 3,500 followers
There's a few more but I'd definitely call that pretty wide distribution right there.....but again, hopefully they show up rendering any discussion about how they should handle canceling totally moot.