This seems excessive, and probably wouldn't be beneficial at all. The malicious users would still get through, okay you would prevent some bots from registering, but there are other types of malicious users that the evil fee prevents.
Ok, with the risk of looking completely stupid, what other types of malicious users do we have around, I count spammers as bots, and we have ban evaders which in most cases are smarter than the usual newbie and in 99% cases know how to use a VPN. What others are there that can pose such a threat?? Of course, you're a moderator and you get access to a lot more data than me, I've also just read the reply theymos gave on the other topic so probably I'm having the wrong impression about this one.