And you don't think that those logs can be faked? It might stop the casual, "hey fans, read this 'book' to support me" but it wont stop the real scammers or people who would buy reads for revenue and ratings.
Kindles are pretty locked down...it's not that difficult to have the kindle sign the data it sends (probably does that already). Being scammed by hacked kindles is one thing, but they're not even trying here...
You could easily sign the log with the same certificate that is providing the DRM on the book itself. Or a different certificate. Encrypting things is not new, nor hard.
You would need to fake the logs for paid accounts, and since rev sharing is a formula of all paid subscriptions, you'd be hard pressed to make positive returns.