•Forgiving
software encourages sloppy practice
•Just because poorly formed objects are usable today doesn’t mean that they will be usable in the future
–Just because a creation or processing tool does not
return an error condition does not
mean the object is correct
–Just because
an object renders does not mean that it is correct
•Since it has become easy to distinguish between the two, we should demand well-formed objects and not tolerate malformed objects