To start with, your Camel book is out of date, but thankfully, http://www.perldoc.com is not. Here is a link to the UNIVERSAL page. You may find this enlightening.

As for my opinion (and I did make a point to say it was my opinion (note the "IMO")) about OO module designers obligations (please keep in mind it is specific to OO modules, as only blessed references inherit from UNIVERSAL). They are my opinions, you and the whole of the perl community have every right to dismiss them as the ravings of a lunatic (believe you wouldn't be the first).

But my assertion that it is bad OO design to break the a method in your base class through some fault of your subclass, actually has nothing (directly) to do with Perl at all. It is just OO design, sure its maybe strict OO design, which Perl is certainly not known for, but if you pick up any (good) book on the subject, I am sure you will find something similar to what I say.