I am on the mailing list, but seldom read it. I just saw this and no one ever informed me of this discussion (sadly). I think your characterization of me and my behavior is incorrect and insulting. Regardless, let me explain...
Android only has "paid" or "free" apps. Android does not support a pay-what-you-want system. So, I rolled my own. I then described that a payment was required in the description, but also denoted in the manifest that this app uses the in-app billing permission. This means that if you either a) read the description of the app or b) read what is displayed on your device when installing "this app uses in-app billing", you would not be surprised.
That feels pretty honest. It is also consistent with how Android apps use in-app billing. In the future, you should understand what you are installing on your device. Let me give an example...
https://play.google.com/store/apps/details?id=com.rovio.gold Yes, angry birds. Notice it says "Free", but says on the page "Offers in-app puschases." This is how Octave showed up too. This also gets displayed at install time. Now you know whether you might have to pay something to unlock part or all of an app.
All that said, I removed the requirement to pay a couple of weeks ago. I will explain that decision in a separate email describing recent changes.