Business meeting business is always by direct democracy. But that's only for electing the MPC members.

MPC business is voted by present members of the MPC. It's conceivable that the MPC could have a quorum at SMOFCon and the argument could be made that, while protecting the MPC and HAMC from conflict of interest (because Hugo nominees might misuse their position on the HAMC to campaign) is a laudable goal, driving away potential Hugo nominees (particularly those with connections to the industry) is in direct conflict with the HAMC's mission to promote the Hugo Awards to the businesses who have the most to gain from the Hugo Awards.