Actually, I don't see anything wrong with creating accessor or mutator methods with Autoload. Class::MethodMaker does that, and it's very useful for simple classes. I've used Autoload to come up with accessor methods. The trick is to document the methods as though they were normal. After all, implementation shouldn't be part of the interface anyway.
Because it defeats the whole idea of having them. The point is you hide the information behind a method interface so if you change the structure of the object then you do not break the interface, there are other reasons but that is sufficient for now. If you have automatically generated methods (which if I understand correctly that is in effect what autoload does) changing the structure of the object will change the interface. Information hiding is a fundamental part of OO and it is not just about having methods to call, you need to understand what is under the hood. This is what I was refering to when I talked about questioning OO ask why why why. A cursory glance at OO is not sufficient.