Kindle owners start to lose text-to-speech on purchased books -- how do DRM-free Kindle books work?

Back in February, the Authors Guild, a lobby group representing less than 10,000 writers, argued that the Kindle's ability to read text aloud infringed on copyright (it doesn't -- and even if it does, the infringement lies not in including the feature, but rather in using it; this is the same principle that makes the VCR legal). Amazon folded and agreed to revoke the feature.

Now comes some news about how they're doing this, from the Knowledge Ecology International site:

Beginning yesterday, Random House Publishers began to disable text-to-speech remotely. The TTS function has apparently been remotely disabled in over 40 works so far. Affected titles include works by Toni Morrison, Stephen King, and others. Other notable titles include Andrew Meachem's American Lion, and five of the top ten Random House best-sellers in the Kindle store.
I've been trying to get a statement from Amazon about this since February: how does disabling text-to-speech work? It appears that there's a text-to-speech "flag" in the Kindle file-format that the Kindle looks for and responds to, disabling the feature if it's set to 0 (a perl script called mobi2mobi can reset the bit to 1).

But what no one at Amazon will tell me is what other flags are lurking in the Kindle format: is there a "real only once" flag? A "no turning the pages backwards" flag?

I'm specifically interested because Amazon has announced a "DRM-free" version of the Kindle format and I'd love to sell my books on the platform if it's really DRM-free. To that end, I've put three questions to Amazon:

1. Is there anything in the Kindle EULA that prohibits moving your purchased DRM-free Kindle files to a competing device?

2. Is there anything in the Kindle file-format (such as a patent or trade-secret) that would make it illegal to produce a Kindle format-reader or converter for a competing device?

3. What flags are in the DRM-free Kindle format, and can a DRM-free Kindle file have its features revoked after you purchase it?

I've sent these questions repeatedly to my contact at Amazon for months with no response. I've tweeted about it. I've sent in requests on behalf of the Guardian newspaper to their press office without even getting an acknowledgement. And I've asked a major publisher that is working with Amazon to release DRM-free versions of its books to put the question to their Amazon rep, and they haven't gotten a response.

I love Amazon's physical-goods business. I buy everything from them, from my coffee-maker to my DVDs. I love their consumer-friendly policies, and their innovative business practices. I just wish their electronic delivery business was as good as their physical goods side. I have a lot of hope for a DRM-free Kindle format, but it's downright creepy when no one at Amazon will even respond to three simple, basic questions about it.

Kindle 2 vs Reading Disabled Students