Well if you want my honest opinion to this quite bluntly, if everyone uploaded a thumb that was within the guidelines this would be a moot point:(    The responsibility for a compliant thumb should be on the person uploading the thumbnail so at this time I feel the way we are handling the violations is the best way.  The guidelines have been in place since January and should be clear as to what is allowed and what isn't.  If a member pushes the line of the policy and are not clear about whether a thumb is compliant or not then they always have been told they have the option of having us take a look before its uploaded to be 100% sure there will be no issue with their image/thumb.  

If 99% of uploads are complaint then to me that says the majority of artists understand what is accepted and whats not.