I have 3 books to send out all requested from different people. Two of the books are library discards. It is in pbs rules that library discards are allowed,but i always send messages stating if a book is a discard. I've run into cases where people prefer not to have a discard. I'm sending all books out wednsday. If I don't hear from the people requesting the books should I still send the library discards?

Frankly, I rarely send PMs about condition.  If I do, then I make sure to include a deadline date.  If I don't hear from them by the deadline, then I send it.  

It's kind of you to PM, but I always assume that if someone objects to something they'll have an RC.  In this case, If I didn't hear from them by Wednesday I'd go ahead and send.

By sending the PMs and not including a clause that you need a reply by x day at y time, you now run the risk of mailing them out on WED only to get a PM afterwards that they do not want a former library book.  That's one reason PBS does not recommend you PM folks about such conditions.....if they have special requirements, they need to put them in an RC.

That's a good question.

Its also why you shouldn't PM asking people if they want a book that is postable when they don't have Requester Conditions saying they don't want books with that condition. It puts you in the spot of "now what?" when they don't answer. If the person doesn't want an ex-lib book, then they need to add a Requester Condition. If they don't have the Requester Condition then just send the book, the requester has agreed to the site's rules on basic condition which allow ex-lib books.

I would send another PM now saying that you haven't heard from them and will be mailing the book on Wednesday since it is postable and they have no RC saying they don't want the ex-lib book.

I never pm the person to ask first. If they don't want ex-library books, they will have requestor conditions to the effect and that is what I will tell them when they complain and try and ask for their credit back.

If there wasn't an RC about library discards then there's no need to PM and just send the book. 

By sending PMs about postable books you set a precedent where some of these people may expect it from everyone and complain if they get a library discard from someone else.  Someone who didn't PM because they don't have to and did nothing wrong.  If people don't want library discards they can set up an RC.

The system is set up so that we don't have to negotiate over book trades. Let the system do it it's thing and just mail the books. 

What they already said  

Because you've PMd  already, I like Melanie's solution:

I would send another PM now saying that you haven't heard from them and will be mailing the book on Wednesday since it is postable and they have no RC saying they don't want the ex-lib book.

If they don't list ex-library books as a "no" in their RCs, I send them.