I just received word from a requestor that they refused a book I sent because it was marked postage due in the amount of $1.02.  I printed the postage and label here at PBS. When I go to the help library it notes that:

This may happen if the item has the wrong estimated weight in the database, and the sender did not correct the weight estimate when she or he printed the wrapper to send the book.

So what happens if the weight is estimated wrong? Do I get my money back or am I screwed?

Buy a scale......weigh the package......change the weight on the mailing label.

You can change the weight on a mailing label?

You can change the weight on the PBS label printing page. Once the label is created/printed/paid for - it's pretty much carved in stone. 

My question is -- does PBS take any responsibility for the wrong weight or is it my" fault" for trusting their weight estimation?

You can ask them if you would like. Use the "Contact Us" button at the bottom of the page. PBS does not normally take responsibility for incorrect weights. I would guess that in most cases they would consider it to be "your" fault ... but who knows, they may make an exception if you convince them your case is special.

But yes, lots of weights are just plain wrong, sometimes different editions of books can be issued with the same ISBN (so the weight might be correct for one edition but not any others that use that ISBN), sometimes members "fix" the weights wrong .... it's best to weigh your packages yourself to make sure the weight is correct before you mail.

From the help center:

The *recommended postage* on my wrapper is/was wrong!

The 'recommended postage' on the PBS wrapper is usually correct, but not always. Our database is compiled elsewhere, and it includes some inaccuracies, including the weight of some books. The weight of a book as recorded in the database determines the "required postage" that appears on the PBS Wrapper.

You can see, and adjust, the weight estimate on the Wrapper Settings page when you go to print a wrapper.  Adjusting it to the correct weight will ensure that correct postage prints out.  If you do not have a postal scale, you can take the wrapped book to the PO to be weighed.

This is particularly important if you are using PBS Printed Postage--check and adjust the weight before you print!  Printed Postage can't be refunded after it is printed.

If you want to change the weight of the book in the database permanently, so that no one else has trouble with this for this book in future, you can submit a correction to our Data Correction volunteers.

• To submit the correct weight of a book to the PBS Database:

1. Click "More Options" to the right of the book cover image on the Book Details page and choose Edit Book Data from the dropdown menu (you can also access Edit Book Data from the Member Tools page, which is linked from the bottom of any page on the site).
2. Enter the ISBN for the book and click Next->
3. Enter/adjust the weight of the book (this will be on your postal receipt) on the next page, leaving any correct information in place
4. Click Submit.

• This information will be submitted to our editing volunteers, and the database should be corrected in a few days.

Please know that any effort you make to improve the accuracy of the database is greatly appreciated.

Side note:  Given the variability of books and the fact that companies regularly re-issue under the same ISBN, expecting any database to be correct on weight isn't reasonable.  I have at least one hardback book on my bookshelf that is the "Book Club" edition.  I also have a keeper book (same title, same author, same ISBN, and hardback) but it is not standard or non-"Book Club" edition.  The difference in their weight is 8 oz which for book weights is a large margin of error.  Which one of these weights should the PBS database weight represent?