Addons don’t actually type “/follow” for you. I just wrote that so it would be easier to understand. They use the FollowUnit API. Run this script in game and you’ll follow your target (can replace “target” with any player name as well):
/script FollowUnit("target")
So they could just disable addons from using the FollowUnit API. Or make it have to be attached to a hardware event (mouse click, button press) like some other APIs already are. I feel pretty confident that Blizzard could find a simple solution to break FollowUnit as a tool to help enable boosting without either hurting chat parsing or disabling following via other traditional methods.