I agree that my explanation probably doesn't account for all of the absentees, I was just giving one reason that I've personally missed events that I've registered for.
I get that you decided to do the event yourself last minute, but I'm trying to make you understand that this in itself will appear highly scammy to other players. Before participating in any event on any player owned area, one must weigh the costs versus rewards. If I'm going to grind on your LA and fork over ~4% (or whatever its set at) of my loot to you for an extended period of time, I need to know that I have a chance at reclaiming some of that. If you as the LA owner are also grinding that same event FOR FREE that becomes a decidedly unfair participant in the event. If I grinded n hours at an increased loss to you and then lost the top prize to you (who did not have the same participation fee) would certainly make me not want to participate in any of your future events. IMO what you should have done in the event given was disqualify yourself (since you were only trying to fill a gap) and given 1st prize to your #2 guy and 2nd prize to your #3 guy. Just a personal opinion OFC, you are free to run your LA as you see fit.