I just happened to see this post in the Book Bazaar and am surprised it hasn't been shared in other forums. The first line is:

As of Sept 1, 2017, ARCs are no longer swappable in any way at PaperBackSwap.

Sharing here so more people are aware of this policy change since I suspect they are shared in more ways than just in the Book Bazaar.  Details are available in the post linked above.

The only place ARCs could be traded before was in the Book Bazaar (they couldn't be posted to our bookshelves, or traded in other forums) so it makes sense to me they would post the info in the Book Bazaar. (Members who don't frequent the Book Bazaar may not have even realized that ARCs could be traded there.) For years, when we've posted a book to our bookshelf, we've had to click to promise the book wasn't an ARC.

Thanks, Val.  I figure that the Team didn't post that information anywhere else for the reasons that Patty stated. :)