The Potential For Abuse With Open Classes
It is believed that open classes provide an invitation for for potential abuse. My argument is that anything provides an invitation for potential abuse, hell I can be sniffing glue in my room for all you know. (No I don't).
It is commonly understood that PHP is repeatedly abused to produce spaghetti code of PHP, SQL, HTML, JavaScript, and CSS. Yummy! This is not a fault of PHP, but a fault of the developers of the spaghetti code. There are alot of new frameworks out there that are based on a Model View Controller design pattern to separate login from presentation. symfony and CodeIgniter come to mind.
Anyone can write spaghetti code in any language. It is the job of the developer to organize code.
Much in the same way in that anything can be done via open classes. It is up to the developer to write good code.
For example Rails comes with a reasonable set of core extensions which don't abuse the use of open classes.
