a) This was suggested as a method to combat random trolling from botnets, so this sort of response is highly unlikely unless you're already getting DDOS'd [1], and b) Fail2Ban allows you to whitelist some IP's that won't be banned, if you really need to protect against that sort of attack.
1: at which point you'd most likely need to be a lot more involved anyways, and you should most likely be running something more serious in front of your server anyways...
1: at which point you'd most likely need to be a lot more involved anyways, and you should most likely be running something more serious in front of your server anyways...