I'm not big on panels. The few I've looked into have seemed to me to be poorly organized. One person can't make it, one is late, and one is just taking up space at the table...
I don't mean to judge all panels this way as I am sure there are some really good ones, I've just not found them myself.
Now, this I suggest for Fan Panels:
Perhaps Otakon already has something like this in place but if not, I suggest that there be a panel deposit. Say the at the door registration fee per panelist per hour. So, a two hour panel with three people would require a deposit of $360.
T