Almost every reply now in the voting thread included the mentioned pizza and probably some did for real while most of them just to get that 1 merit. But here's a thing the user mentioned in OP doesn't seem to be a merit source so he will run out of sMerits to merit if hundreds of them decided to do it.

Even though there is no explicit rule the note mentioned in it can be used for such and if icopress consider this as any kind of violation or manipulating the voting process then there's always a chance for disqualification.