Not so fast. Anti-circumvention laws are everywhere, we aren't talking about EULAs here.
The DMCA act in the USA prohibits DRM removal, under all circumstances, even if we are talking about your own content for which you own the copyright.
In Canada bill C-61 also made DRM circumvention illegal. In Europe too. It is unclear to me how these fare to the DMCA, because it might be that only providing the tools and information for doing that is illegal. But in Europe, even if we are talking only about the tools being illegal, if you end up removing the DRM protections from some content, it can be argued that's changing the format, which is a different thing but also illegal.
It is worth pointing out that pieces of software, like CloneCD [1], are illegal even in Europe, even though this software only makes exact copies and does not change the format (it does not remove DRM).
And the US, being the 800-pound gorilla that it is, is constantly pushing others for copyright reforms similar to the DMCA.
Also, whenever you're talking about "fair use", you're always in a gray and dangerous area, as fair use clauses are intentionally ambiguous, so sentences are passed based on subjective reasoning based on context and in the US on precedents. If fair use is your defense, then more often than not you're screwed if you can't afford competent lawyers.
[1] http://en.wikipedia.org/wiki/CloneCD