While I agree CloudFlare handled this poorly, there is this reply on the blog from Matthew Prince (CEO of CloudFlare): Both enabling "I'm Under Attack Mode" or

While I agree CloudFlare handled this poorly, there is this reply on the blog from Matthew Prince (CEO of CloudFlare): Both enabling "I'm Under Attack Mode" or routing the traffic direct are both supposed to generate an automated message to the customer letting them know what happened. We've reviewed the logs and don't see a message having been sent. I'm investigating why that didn't happen since I agree it is not acceptable.