When non-activated users try to share a post, they are sent to a warning page which currently lives at:
which looks like:
I think calling out this restriction is good, no problems with the UX flow. But I also think this should be just a pop-over on your feed or some other form of modal dialog, not navigating your browser to an entirely separate page that makes me lose my place in my feed. Hell, I'll take a JS alert dialog + AJAX request.
Picture says a 1000 words, so please take this highly detailed and extremely high quality mockup I made in Paint in 2 minutes while in a meeting at work:
I don't know what this workflow looks like for an activated user!