Yes - via prpoer weighting you can specifiy that a layer is not allowed to have labels placed upon it... However this will affect the drawing of all labels. Sometimes their are multiple feature classes that have symbiotic labels that live quite harmoniously with a particular layer and you do not want to upset this. Yet there will be one large label that covers up too many important features. if you weight the feature for no encroachment there are wonderful open spaces found for those large labels just where you had wished they were placed - But all those previously symbiotic labels are no longer happy!
Sometimes it is just one problematic set of labels that you wish to keep away from features - It would be "Oh So Nice" to have the option to restrict this set of labels to fall away from certain features.