I'll test it with this post, just for fun. Does it give the user enough warning that it will be hidden for everyone? Does it just do it without any friction? If so, should friction (e.g. a warning) be applied? Or should the "Hide" button be renamed to something less confusing?
Topic on Talk:Structured Discussions
Nicereddy: After hiding & unhiding the topic, I'm satisfied with the current iteration. The warning is a bit ugly, but that's not a huge deal.
I will say that the reasoning for hiding the topic should be available on the Flow page itself, rather than just its "View history" page. I'm not sure if that should be placed regardless of whether or not the post is collapsed, but it should probably be placed in a more user-facing location.