public PlayerInfo AddUnrecognizedPlayer( string name, Rank startingRank, RankChangeType rankChangeType ) {
if( name == null ) throw new ArgumentNullException( "name" );
if( startingRank == null ) throw new ArgumentNullException( "startingRank" );
int id = GetNextID();
PlayerInfo info = new PlayerInfo( id, name, startingRank, rankChangeType, false );
trie.Add( name, info );
return info;
}