Meaning of "don't ask don't tell"

Solution 1:

No, this is the name of a specific policy regarding gay servicemen and women in the US military. It is not a general term in the military or elsewhere.

(If you see it anywhere outside of this context, it is almost certainly at least making reference to the military policy, e.g. a satirical reference.)

Solution 2:

The Occasional Pamphlet has an article where "Don't Ask, Don't Tell" is used with regards to rights retention policies for scholarly articles:

A strange social contract has arisen in the scholarly publishing field, a kind of “don’t ask, don’t tell” approach to online distribution of articles by authors. Publishers officially forbid online distribution, authors do it anyway without telling the publishers, and publishers don’t ask them to stop even though it violates contractual obligations. What happens when you refuse to play that game? Read on.

Susan Signe Morrison also has Don't Ask, Don't Tell: The Wife of Bath and Vernacular Translations', Exemplaria 8 97-123 which according to Louise Sylvester & Jane Robert's Middle English Word Studies: A Word and Author Index in page 152 -

Discusses the importance, particularly for women, of the translation of texts, especially medical texts into the vernacular

Solution 3:

This phrase, ostensibly coined by military sociologist Charles Moskos, did appear in print prior to its current use—but not very often. It certainly was not a catchphrase. Here's an example from a late 1970s journal on terrorism:

and an earlier one from a 1968 issue of Mademoiselle:

You may still find don't ask, don't tell used outside the direct context of the US military's policy on homosexuality, but because of its minimal use before this policy and its widespread currency resulting from this use, @Kosmonaut is correct that these uses give a nod to its military mileage. I can't think of any way this phrase could now be employed that would elude its current connotation.