Exactly. What should be done is just get a list of records that were requested by/requested for these users that you will be deleting before you do so.

This can be done doing the following:

deleteUser();

function deleteUsers(){

  var target = new GlideRecord('sys_user');

  target.addNullQuery('user_name');

  target.addNullQuery('email');

  target.addNullQuery('ldap_server');

  target.query();

  while(target.next()){

  var taskRecords = new GlideRecord('task');

  taskRecords.addQuery('requested_for', target.sys_id );

  taskRecords.query();

  while(taskRecords.next()){

  gs.print("The record " + taskRecords.number + " is associated with sys_user record" + target.sys_id);

  }

  //Uncomment the following line when you want to commit the delete

  //target.deleteRecord();

  }

}