The notion that saying the event's reward (the scroll) would be available latter, before the event had actually occured, would then lessen attendance is a cop out. This would be admitting the real reason people went to kill Exodus (even before the scroll was revealed) was for an item, not for the event itself. If the item is the sole draw for many people then we have a serious problem.
With respect, we already know that this problem
does indeed exist. On Great Lakes, we discuss it inside the RP community on a near weekly basis, and I can say that
without playing every week. We have had many discussions about events, items, and the effects they have on event turn-out.
And it's not a cop-out to suggest that advanced knowledge of either the item, its significance, or its drop-rate would have had adverse effects. In truth, given that it was a global arc, and global arcs tend to have items dropped, you can definitely bet most people thought there would be an item dropped. Now, the other unique item, the book, the one that everyone and more could get... I mean, is that any different than the display pedestals? Yeah, I'm sure a lot of people don't care about the book -- which is sad, but also attests to the very thing that you are questioning:
The real reason (many) people went to kill Exodus was for an item, not for the event itself.
People should want to go to events like this (and the normal EM events) because they are fun community activities that enrich a shard's fictional history and bring people who might otherwise never play together into contact.
Should versus Reality. Unfortunately, Reality wins.
This whole situation could have been avoided with a few lines of text in the Call to Arms post.
It didn't need to be avoided. I mean, really... I prefer my events to be without foreknowledge of what's coming. I also think most people are grown up enough, if not necessarily logical enough, to discern for themselves that permanent, character altering rewards aren't going to be unique. Remember, because a lot of old Seer items were duped and spread themselves around pretty widely, the Dev Team decided to do the correct thing and add them in as drops. So on and so forth.
There really wasn't anything that needed to be avoided. We, the community, caused the vortex of rumbling all on our own.