Yes, that definitely seems to be what they do, and I understand why that frustrated the user. I think the CEO should have taken the frustration as feedback, even though the user wasn't very tactful on Twitter.
The user wasn't very tactful on Twitter but the CEO ramped that up to maximum levels with calling the user an "ahole"..
> I was expected to stay on top of them or risk an automatic “upgrade” from $36 to $99 for having an extra staff user on my website? I had forgotten about this, but why not just block me from adding them?
So looks like Ghost allows you to add more members freely, does not warn or tell you anything when you do it, but then only tells you that you'll be upgraded automatically via email later? (It's partly a rhetorical question, but I genuinely don't know how it works).