Protected and private slots

[Caleb Tennis]

I've always been using protected and private slots under the guise that 
connecting to them was prohibited based on conventional C++ rules, as stated 
here:

http://doc.trolltech.com/3.3/signalsandslots.html

However, after some recent experimentation I've found that I can always 
connect to and use protected and private slots.  For example, in pseudocode:

class TrySlots: public QObject
{
  Q_OBJECT

public slots:
  void myPublicSlot() { qDebug("myPublicSlot"); }

protected slots:
  void myProtectedSlot() { qDebug("myProtectedSlot"); }

private slots:
  void myPrivateSlot() { qDebug("myPrivateSlot"); }
};

  QApplication app(argv,argc);
  TrySlots ts;

  QObject::connect(&app, SIGNAL(aboutToQuit()), &ts, SLOT(myPublicSlot()));
  QObject::connect(&app, SIGNAL(aboutToQuit()), &ts, SLOT(myProtectedSlot()));
  QObject::connect(&app, SIGNAL(aboutToQuit()), &ts, SLOT(myPrivateSlot()));


The connections always work, and the slots are always called.  I've tried a 
number of iterations and variations and I'm always able to call protected and 
private slots from any signal.

Is my logic just way off for a Friday morning or is something else amiss here?