Community site Pet Food Alpha has reported that Square-Enix is specifically targeting players who own more than one character for the explicit reason of gardening. Any level character can garden -- even right from the start of the game -- but no character can have more than 10 flowerpots at a time in their house. This has sparked players to purchase more character slots to simply expand their gardening enterprises, a common practice that has been done by players for over six years.
Players are unclear if these bans have been handed our by individuals on the RMT Task Force, or if they bans were created by one of Square-Enix's new automated tools. We'll keep our eyes on this story and update as new information comes in.