Filters

add_filter( 'rtm_set_album_cover_label', 'rtmedia_set_album_cover_label', 10, 1 );

function rtmedia_set_album_cover_label ( $label ) {
    return 'Make Album Cover';
}

add_filter( 'rtm_allow_set_album_cover_art', 'rtmedia_allow_set_album_cover_art', 10, 3 );

function rtmedia_allow_set_album_cover_art (  $allow, $media_id, $interactor  ) {
    if ( $interactor == get_current_user_id() ) {
        $allow = false;
    }
    return $allow;
}