I don't think GenCon really cares much about lineup complaints. Honestly, it's probably not that big a deal to them. It pissed some people off, no doubt about that and mightily so but I don't think it cost them anything in the end other than some choice words.
Any reason it would have to be in April?
No, not particularly but it seemed to work pretty well that time and it's sort of slow for conventions in some respects. Well, aside from Colman nearly freezing to death it worked well.
It is possible it would be in may around the 30th Aniversary, and it is also quite possible that it is registered under a psedo-name to keep it under wraps.
Yeah, I considered that as well and it's a perfectly valid point. If it's not in April, then the 30th anniversary makes great sense, I just thought they might have an easier time getting space for April rather than May.
That Fire Department Instructors Conference seems awfully large and long in duration. Though a google search reveals it is a real event. Still, the 2007 event is 10 days long whereas the 2006 event is only five days long. Hmmm....