That's an interesting point of view. If you are just starting a forum, the spam may be manageable by conventional means such as captcha, Q&A, and old school moderation as you said. As you expand and get more traffic, even for a small-mid size forum, things get out of hand very fast. Factor in moderation time, negative impact on the brand's image, and ineffectiveness of conventional solutions on a larger scale; these things cost the administrator much more than the members would be paying to register, put together! Imagine how your volunteers could be used to spend their time and resources into creating positive change on your forums rather than destroying negative spam.

That said, members paying to register seems to be a recurring concern and I would just like to throw the idea out there that you can simply refund the fee. Thank you for inspiring this concept; maybe I will work it into the modification as a feature!!! :)

I work on making the modification right for as many people as possible! :)

Well, it wouldn't be a bad feature, but like I mentioned before I think it's more the idea of providing payment information rather than the amount. I do see your point of paid registrations making your forum seem more valuable, and if a forum is established and not desperate for new users then it might not be as bad to add another registration hurdle. But of course not everyone is in that situation.

Oh, I did not know it was about providing payment information. All payment information is stored at the processor (e.g. PayPal), and your address, in the case of Paypal, is only released if you are receiving tangible goods. Are there any other big concerns?

Yes, besides driving people who can pay you have to understand that not everybody has the ability to pay on the internet as well. There are countries in which paypal and other payment processors dont operate. Besides that not everyone has access to online payment modes.

Also please stop peddling your semi-commercial mod so aggressively. You may well believe in the value of your mod but others may not agree with that.

A vouching system could mitigate what is projected to be a very small issue; interesting point nonetheless! What, in your opinion, percentage of people in the average forum's target audience does not have the ability to pay [and get refunded] over the internet?

vBulletin supports quite a few payment processors out of the box (Paypal, NOCHEX, Worldpay, Authorize.Net, 2Checkout, Moneybookers, CCBill) so country restrictions should not be a huge concern. What country does not support all of those?

Peddling? Semi-commercial? Very strong words! The subject of this thread is spam being out of control and the ineffectiveness of Q&A implementations. What do you feel is semi-commercial about the paid registration mod freely available and supported here?

Stick to the topic please.

All the capchas in the world won't stop human spammers, and to answer the OP's original question, yes it probably is a human using google to answer that question.

How often does it change because if they can answer it once and add it to a database somewhere they never need to worry about it again.

Is your forum mostly specific to 1 country or area? Moderating entire countries from joining might be an option. https://vborg.vbsupport.ru/showthread.php?t=231315 - The mod is for 4.x but I think it will work on 3.8 too.