When countries opt for non-intervention, they opt first and foremost for a hands-off or laissez-faire approach; thus, they pay no heed to problems as they arise and allow power struggles to run their natural course in the circumstances. In practice, non-intervention is an actual choice, a plan of action that generally plays out in favour of the country's dominant or official (de facto) language. In principle, countries or states choose NOT to intervene if they don't see the need.
Non-intervention policies are, in principle, unwritten…and unofficial. Still, they don't prevent governments from issuing statements of intent or implementing administrative procedures, or even enacting regulations or decrees, if not a series of vague legislative or constitutional provisions. That said, non-interventionist governments do not pose as arbitrators, and they resist any temptation to adopt very specific laws or regulations. And in justifying their approach, they often advance concepts like freedom of choice, tolerance and openness to differences.
Here again, the term "non-intervention policy" can appear ambiguous, because states do some times practise intervention and non-intervention all at once. For instance, they may choose not intervene when it comes to the official language per se, but may decide to protect minority languages; or they can act to promote the official language and refrain from protecting minority languages; or they go the opposite route and promote minority languages and leave the official language to its own designs. Ontario, for example, hasn't intervened with legislation for its official and majority language, English. But for French, the province adopted the French-Language Services Act. Other provinces have opted for total non-intervention, no matter what the language, which can of course hinder their minority-language groups. But as time goes by, Canada's English-language provinces are turning their backs more and more on non-intervention.
A few examples of non-intervention at work in the world: Liechtenstein, United Kingdom (until 1998), Angola, Argentina, Uruguay, Venezuela, and a few American states including Connecticut, Delaware, Iowa, Maryland, Nevada and Rhode Island. Other countries or states have never intervened to manage their official language but have passed laws or legislation for minority languages: Germany, Austria, Congo-Brazzaville, Equatorial Guinea, Czech Republic and, in Canada, Ontario, Nova Scotia and Prince Edward Island. Finally, some countries and states have intervened for their official language and not at all for minority languages: the American states of Alabama, Arizona, Arkansas, California (23 in all), the principality of Andorra, the countries of Iran and Egypt, and certain overseas departments of France (Martinique, Guadeloupe, French Guiana, Réunion Island, Wallis-et-Futuna). It's estimated that roughly 30% of the world's soverign states practise non-intervention of some form or another.