That's correct but this not a parimutuel wager, it's fixed odds; so if you take Atlanta at 3 to 1, you will be paid 3 to 1 for Atlanta winning regardless of what other folks bet. In parimutuel your payout would adjust according to the rest of the money wagered until the betting closed. Horse race bets are often parimutuel, but most proposition bets such as these are not.

The books can be wrong, and the betting markets aren't perfect but they can be useful tool to gather what the rough consensus is at any given time.