Marked a book RWAP on August 27 because it had brown stains all down the sides of the pages from coffee or another such liquid.  As of today, I got no response from the sender, so under problem followup I marked that the sender did not reply to my PM to discuss the problem.  After marking it as such, I got the following message from PBS:

Thank you for your followup concerning this problem swap. We will contact the other member.

Does PBS really contact the other member?  I thought PBS did not get involved in individual RWAPs, so this message surprised me.  Or is it because the sender didn't reply to my PM?

Or is it because the sender didn't reply to my PM?

Yes, this is why. It is true that they don't get involved in swap issues as a rule. But, if te othe member won't respond, they will prompt them to answer you.

PBS will try to contact the other member.  This is because the sender didn't return your PM to resolve the issue.  PBS doesn't get involved with individual swaps because they can't know the condition of the book, etc but they will get involved if the sender doesn't even try to communicate. 

I hope it works out for you.

"We will contact the other member"  just means the system will send an email. It doesn't mean they're going to call him or suspend his account or force him to answer you.

The sender buddied me back a credit. Wow! Thanks for the replies everyone.