About the only thing I could think of is, limit the rate and see what accounts keep trying to post even though they fail? But there would be so many false posi

About the only thing I could think of is, limit the rate and see what accounts keep trying to post even though they fail? But there would be so many false positives on that idea. Would punish many that are legitimate users and probably harden those that have more sophisticated posting techniques. Like you said, there are better ways.