That is more than just a theory, their own documents (I can't remember if they were leaked or officially released as part of the big anti-trust case) stated that this was essentially their policy for poor eastern counties: if they wouldn't be paying for it anyway MS preferred them to use it rather than something else (like Linux, or something locally created, etc,).

It was less openly ignored in the case of students, or people using work licenses (or just pirate copies) at home, but the above and the lack of enforcement would indicate it was ignored for that reason.