[CM30]

The issue is that AI bots can answer pretty much any captcha that isn't ridiculously obtuse. Your homemade captcha can be solved with an LLM, but so can the latest version of Recaptcha or whatever.

But I feel that there may be some other tools here. Spammers in general tend to be fairly predictable in their behaviour, so tracking that could help. If a member is including links to a third party site in dozens of messages, that should be a pretty big hint that their intentions are questionable. If they blast through the registration page in seconds, same thing.

Personally, I've not seen more than a single spammer on the forum I run for the last 6 months or so, so I'm still optimistic that most don't bother unless it's easy to attack and worth their time.