Could just be a trial balloon
This could simply be the same thing politicians (especially in Washington) do all the time: "leak" a rumour and see how the market reacts (and you're right in that it does not have to come from Apple, seeking to provoke a reaction there).
From our perspective, we would not mind the permissions for loading unsigned apps buried a bit deeper but barring it altogether would stop us from upgrading until Apple saw sense. There's also a lot of experimentation taking place on the platform, and blocking it would stop that - I don't think Apple can afford taking that risk.