It's pretty neat how much Cloudflare gives you for free. I just added some firewall rules for the Avian Waves website. Now when you attempt to register an account, it will do a really quick scan to make sure you are not a malicious bot or spammer. In addition, I am using Cloudflare's threat score system to do the same check for IP addresses that are in blocks of known spammers or other malicious actors. If it isn't sure, it might ask you to solve a CAPTCHA. Sorry, I know it's annoying, but hopefully it cuts down on forum and blog spam as well as fake user accounts. And it should only bug you with a CAPTCHA one time.
If you are having trouble with anything due to this, please contact me at the link above. Include your IP address.