A number of data items are selected for inclusion in a data set so as to discourage a transmission of the entire set over a limited bandwidth communications path, such as the Internet. The data set includes an entirety parameter that is used to determine whether the entirety of the data set is present. In a preferred embodiment, the entirety parameter is a hash value that is based on watermarks of each data item. When presented for rendering, the watermarks of the data items in the presented material are read and a hash value based on the presented watermarks is computed. A mis-match between the computed hash value and the entirety hash value contained in the data set indicates that less than the entirety of the data set is being presented, and the rendering is prohibited.