I'm sorry if this upsets you.

Spammers and the software they use are already on top of the security challenges that various boards have.

If there was a better solution to the problem, it would have been put in place by now.

I've frequented several boards over the years, open door jobs like this one, ones with registration, capcha, and whatever else. They all still get spammed. Nothing changes, but it makes more work for those that have to clean up the mess

I could go on, but I don't want to waste my time or yours. Let's just agree to disagee, yeah?