With my own assessment of voting dynamics (possible voting strategies), I was still o.k. with a contest participating member to vote for his own pizza while I was personally presuming that a member could vote for his own pizza and not vote for any other pizza. Accordingly, at this time a person could give all his voting weight to his own pizza and sacrifice his other 4 possible votes by voting only for his own pizza since there is no need for any voter to have to execute all 5 of his votes.
True, but that just ensures that all 144 pizzas had one vote. It would not have that much impact on the final vote.
Of course, everything will depend on how many users will vote, but even so I don't think it would have a significant impact.
In any case, the organization will be able to more easily verify whether this has had an impact on the votes or not.