The amount of ignorance about this is crazy. It's not a deal till its signed. Teams have every right to pull their offer before it's signed just as the players has every right to change his mind and go to college. The Braves are hardly the first team to do this and if I bet there's atleast 10 other occurrences in this draft alone where a team pulls an offer.
Obviously they don't because if that were true the Braves would've been able to pull whatever offer they had with the other player to give to Anthony.