Well, that can be controlled with individual preferences if the parameters are set in place to deal with those subject materials.  But, sometimes, the filters are too broad to be specific and certain "subjects" can eek through the cracks when it's unexpected.  As Wolfenshire alluded to, diligence and reporting those violations are the best measure ATM unless they become a major problem in the future.  And lets forget parental controls, there are minors that frequent the gallery whether we like it or not.