PHP5 and the DOM model

Hello! Seems that PHP gets more and more object oriented, which is good. I am now running a course in PHP, using PHP 5, where we are going to use the *DOM* interface. I am trying to teach them good OO practices, meaning that we insistently hide properties and expose them as get or set methods. Looking at the PHPs *DOM* implementation, I see that many of the properties are exposed directly, without even offering get methods. 1. Is there something I am misunderstanding orotherwise missing? (I havenot used *DOM* in PHP before). 2.This poses a pedagogical problem for me as a teacher. How do I explain this contradiction to my students? Thanks Michael