You know what would be bloody brilliant?
Invitations.
Make up some little embossed invitations that would be like, tickets to the Tea Party. Figure out how many servings of cake there will be, then make sure that only that number of invitations are distributed. It will be a good way to cut off the line that is sure to be huge next year, and also give attendees a lovely little keepsake! Also, if people wanted to, oh I don't know, request an invitation before the convention then maybe Kyouya could be convinced to mail them one for a modest donation? <_<
All funds go to cake after all.
That's much better than death.