note 86266 added to language.oop5.visibility

WHEN do I use public, protected or private keyword? Here's the default behavior.
<?php
class Example
{
  /* use PUBLIC on variables and functions when:
   *  1. outside-code SHOULD access this property or function.
   *  2. extending classes SHOULD inherit this property or function.
   */  
  public $var1;
  public function someFunction_1() { }

  /* use PROTECTED on variables and functions when:
   *  1. outside-code SHOULD NOT access this property or function.
   *  2. extending classes SHOULD inherit this property or function.
   */
  protected $var2;
  protected function someFunction_2() { }

  /* use PRIVATE on variables and functions when:
   *  1. outside-code SHOULD NOT access this property or function.
   *  2. extending classes SHOULD NOT inherit this property or function.
   */
  private $var3;
  private function someFunction_3() { }
}

# these are the only valid calls outside-code can make on Example objects:
 $obj1 = new Example();      // instantiate
 $var1 = $obj1->var1;        //  get public data
 $obj1->var1 = 35;           //  set public data
 $obj1->someFunction_1();    // call public function
?>

Now try extending the class...

<?php
class Example_2 extends Example
{
  // this class inherits the following properties and functions.
  public $var1;
  public function someFunction_1() { }
  protected $var2;
  protected function someFunction_2() { }
}

# these are the only valid calls outside-code can make on Example_2 objects:
 $obj2 = new Example_2();  // instantiate
 $var2 = $obj2->var1;      //  get public data
 $obj2->var1 = 45;         //  set public data
 $obj2->someFunction_1();  // call public function
?>
----
Server IP: 69.147.83.197
Probable Submitter: 67.150.124.172
----
Manual Page -- http://www.php.net/manual/en/language.oop5.visibility.php
Edit        -- https://master.php.net/note/edit/86266
Del: integrated  -- https://master.php.net/note/delete/86266/integrated
Del: useless     -- https://master.php.net/note/delete/86266/useless
Del: bad code    -- https://master.php.net/note/delete/86266/bad+code
Del: spam        -- https://master.php.net/note/delete/86266/spam
Del: non-english -- https://master.php.net/note/delete/86266/non-english
Del: in docs     -- https://master.php.net/note/delete/86266/in+docs
Del: other reasons-- https://master.php.net/note/delete/86266
Reject      -- https://master.php.net/note/reject/86266
Search      -- https://master.php.net/manage/user-notes.php