I will repeat what I've said in previous years: This is supposed to be a fun little* event. If someone tries to ruin the fun they will likely be disqualified anyway. And if this stops being fun for people it will stop being organized.
Let's call this a social experiment with prizes. From the start, I didn't want to create rules for every conceivable case, caveat and exemption. There is no such thing as a perfect system anyway.
So far nobody ruined our fun and am hoping this will continue this year!
* This is not such a little event anymore. Las year we had a record 50 entries, now over double that... 113 pizzas! Thank you @John Abraham for you help in posting the (many) entries that were missing.
As every year, I truly am hoping our fun won't be spoiled this year either because some of us have some big ideas for next year's event!
If I can suggest a valid alternative for next year, I suggest you keep the contest within the forum and use the merit system for voting with the max limit. of only 1 merit as a vote. This does not allow external votes and keeps the vote closely linked to the pizza and its success.