I've lied about my birthday while signing up for websites before. I've also made ad-hoc email addresses with forwarding to conceal my main email address. I've given fictitious phone numbers and I've used the names of fictional characters. I do this because I benefit from the service but I don't trust the provider to use my information responsibly.
Not a logical leap to go from there to feeding fake data to extensions when they request data that the user deems unnecessary for their functionality.
I believe if you ask for very wide permissions, at least when publihsing a browser-extension in the Google Chrome-store, you will have to justify why those are needed (from a user-facing POV), and your extension will be subject for additional review.
The same also applies when creating other Google-related apps which uses APIs which Google deems sensitive or restricted: You will have to justify their usage and be prepared for a review.
It's not bullet-proof, but it's more than nothing.