To 'imagine' the death of the monarch constitutes an act of treason under the Statute of Treasons. Elizabeth did not 'appoint' James VI of Scotland as her heir, or anybody else for that matter. And given the gruesome penalties for treason, people had to be fairly discreet in their speculations as to who the next monarch would be. Even as she lay dying her courtiers had to be rather circumspect in their words and actions.