Which idea is stupider?

[J. J.]

Convention advantage.  The conventions are so far away from the actual election that any effect they might have is lost once the real campaign begins. 

At least with the neighboring state advantage there is the potential for demographic and ideological similarities between the states.  So it follows logically that if two neighboring states have similar kinds of voters they are probably going to like the same type of candidates.

You can have media market spillover.