"... what does the namespace declaration and halting error due to its omission accomplish for me?"
It encourages generation of proper XML.
If consumers accept invalid XML, guessing at what it's supposed to mean, then producers will become sloppier over time, since there's no penalty for failing to follow the specification. Eventually producers will be so sloppy that producers will no longer be able to make meaningful guesses.
It encourages generation of proper XML.
If consumers accept invalid XML, guessing at what it's supposed to mean, then producers will become sloppier over time, since there's no penalty for failing to follow the specification. Eventually producers will be so sloppy that producers will no longer be able to make meaningful guesses.