Ya'll got me thinking about this so I looked up the Braves' policy. "All cameras must be hand held and no longer than 5" in length. No tripods or monopods will be permitted. Hand-held video cameras and still cameras for personal use may be brought into the ballpark, provided no game action is recorded in accordance with Major League Baseball regulations. Please be courteous to those guests around you when taking pictures, the equipment may not obstruct the view of other guests. Camera cases must fit through the bag template and will be inspected prior to entrance into the ballpark."
I have a 3100 with just an 18-55 and a 55-200 lens so I doubt I'd be over the 5" size limit. I have taken it with me now to 4 games and have never been questioned. Going again on Sunday, hope they don't say anything!