I would imagine it is not just a ban from the website ui. It is most likely a server API. The game isn't played just by blockchain transactions. Whether the bot is using the website or not, it is going through the Splinterlands servers. Think about when the game goes down for maintenance and is inaccessible, they aren't bringing the entire blockchain down, just the game. A ban essentially does this, isolated to an account. So if they actually detect botting from an account and wanted to ban it, they definitely could. They just don't want to.