I don't think it's ShareCG's fault that people abuse the system. It should go without saying that the site wants quality items. It is a business site after all and crap doesn't pull in the good advertisers or customers. Could that Poser upload page be worded better? Probably. It wouldn't stop people who are going to abuse the system though. That's going to take some direct intervention which I do believe they're doing now.

It is a miracle that curiosity survives formal education. - Albert Einstein