I imagine they haven't released official APIs yet because they want to retain the freedom to change things at will while they explore the product space. Makes sense to me.
Transition periods, documentation, and warnings all take time and effort that might be better spent on the relatively new product.
Until they endorse a way to access Google+ with an API, anything you do is at your own risk.
I thought this same thing when I read it the post. Last I heard, people were complaining that Google didn't release any APIs for Google+. Now someone is complaining that these unreleased APIs are broken?
Hacking doesn't mean "I got it right", it means "I got it, right?" You don't depend on hacks to get you through your release, you depend on hacks to get you through the night. And make no mistakes, writing any application around unreleased APIs is hacking. Thousands of hours down the drain and hundreds of thousands of users with a broken experience... seems like there should be a lessons-learned here, and it's not all on Google's part. Google doesn't have to notify developers of anything if Google's stance is "we don't support third party development yet".
They released a limited API that lets you access public posts that has been relatively stable for me. Their data model is pretty complicated and I'm always learning something new but I haven't had anything break retroactively except some token refresh.
I agree that they'd want to limit widespread usage until they get it right.
Transition periods, documentation, and warnings all take time and effort that might be better spent on the relatively new product.
Until they endorse a way to access Google+ with an API, anything you do is at your own risk.