The law on Digitial Rights Management systems and the breaking thereof is not murky at all. Unless you have a valid exemption: it's illegal (unless of course you lie somewhere where it isn't the local rule of law).
The other thing people are shocked by is that Customs does take this stuff [i]very seriously.]/i] Entering the US with a Kindle that has broken ebooks on it could result in prosecution that puts you at risk for up to $250,000 per ebook they find on your Kindle (and possible jail time). If you think I'm kidding just cross the border into the US and declare to them your Kindle is packed with broken ebooks and see what happens.
Ditto for entry to Canada and the EU (although the dollar amounts vary)
Even better: Customs does not need a search warrant. They can demand your Kindle, drag it off behind the scenes and make a copy of the files on it. A few months later you wind up in handcuffs. Even better, the courts are now agreeing that Customs can Fedex you your Kindle later if they need more time to copy it.
Recently various Customs agencies have been copying increasing numbers of digital devices crossing borders in an effort to crack down on trafficking in child pornography. Legally though they are required to report any violations of law they become aware of during an investigation.
That's all cut-and-dry to me. What I find interesting to discuss is:
Does Amazon's DRM system's permissiveness constitute "written permission" as demanded by the statement in the above example ebook? The above ebook demands you only have a single copy of the ebook and can't transfer it to anyone that didn't also purchase the ebook (note: not paper, ebook).
Now that's what I call "murky" and I'd appreciate a statement from Amazon covering it.