Wikinews:Ignore all rules
In the main namespace
A number of the policies applied to articles are de-facto non-negotiable. In particular, all articles which are published for indexing by news aggregators, or displayed in RSS feeds, must be subjected to independent peer review.
Regarding common conventions in writing, the introduction to Strunk's The Elements of Style gives a succinct justification for breaking the rules:
It is an old observation that the best writers sometimes disregard the rules of rhetoric. When they do so, however, the reader will usually find in the sentence some compensating merit, attained at the cost of the violation. Unless he is certain of doing as well, he will probably do best to follow the rules. After he has learned, by their guidance, to write plain English adequate for everyday uses, let him look, for the secrets of style, to the study of the masters of literature.