You needn't read or analyze everything just the stuff that is reported and since 90% of the problem is 1% of individuals if you can keep the same old folks from coming back you will ultimately have less to process. The logical thing is that the kind of human moderation that they actually needs costs money and you acquire said funds by charging monthly. This has the side effect of making it easy to permanently ban problem children via their address and or method of payment. One need not take prepaid cards either.