Sholdn't the system NOT allow book mail dates to reflect days the PO is totally closed?  Like Sundays and Federal holidays?

I have books enroute to me that show they were mailed last Sunday or on Presdent's day (last MON).   

I thought when I choose a date to mail a book out that it doesn't allow you to choose a Sunday, but I must be wrong about that.

Sunday is greyed-out because post offices are closed, but you can still choose it. 

I usually mail my smaller packages by dropping them in the blue box while I'm walking my dogs. I walk them every day of the week, and I mail bills and packages whenever I happen to have them ready to go. Once my mail is in the blue box, regardless of the day of the week, it has been mailed. 

Just because the P.O. is closed doesn't mean people can walk in, use the lobby machine to buy postage, put it on the box and drop it into the drop box inside the P.O. I've done that tons of times.

In fact, Sundays can be the easiest time to find parking.

I have a 24 hour APC at one branch.  I've heard that there are several 24 hour branches at mail hubs or airports.  We can also use printed postage at anytime.

I mail many of my books from Meijer because they offer postal service from 7AM to 9PM 7 days a week.  It's great because during the week it's difficult for me to get to the post office before they close and it means that that I can get books in the mail on Sundays and federal holidays when I have more time to get out and about.

It is a misconception that the PO is closed on Sundays and most holidays.  The post delivery people and the desk is closed but all the background work is going on.  Some small PO are actually closed but the bigger ones are just closed to the general public.  They are still accepting mail and Business mail still drops there mail off at the PO.  On presidents day we got no mail delivery but at work we sent  out about 5 pallets of mail.  We also send out metered mail that day.  So I have mailed things out on days most people think the PO is closed.

I mailed a tea package with Custon DC for the tea swap late last Saturday afternoon, after the PO had closed and it was scanned that evening (or early Sunday). So they obviously emptied the blue box afterwards.  I also frequently drop books in the blue bin on Sundays and Holidays.  They're still mailed even if they don't get picked up for a day or two.

Also you have 2 days after the mail by date to mark a book mailed. So even if you go to the post office and the mail by date is a Sunday or Holiday-you can just mail the next day.  You are also allowed to mark a book mailed before mailing it as long as you mail it within in 48hrs. 

I'm guessing that with all these factors it was just easier for them to include all days instead of making it block out Sundays and holidays completely.

Also, imagine that if you didn't take into accounts Sundays and Federal Holidays, that would mean adding an extra day or two to the mailing process. Assuming that you choose the last day to mail but that happens to be a Sunday, followed by a Federal Holiday, it means that Tuesday would be your last mail by date. If you add 48 hrs. to that, then we're saying that in the usual scenario, you'd have to mail by Tuesday while in the second one, you'd have to mail by Thursday.

People complain as it as it about how much time people have to mail so I'm not sure this will be a welcome change.

My little PO often puts out mail and such on a Sunday.  Just because the counter isn't open, doesn't mean they aren't working.

I mark a book as mailed when I put it in my mailbox.  Better to mark it mailed while I'm thinking about it, then to forget to visit PBS later to mark it mailed.

Also, Sunday in Georgia, where PBS is based, may be still be Saturday in Hawaii, but Monday in Guam.  We have members in all those places.

When people click "Book Mailed" they are making a record of the exact time they clicked on the button, not the exact time the book was mailed.

It is not an accurate reflection of exactly when the book was mailed. it is approximate, and always has been. Usually people click the button on the same day they mail the book.

I mail almost all books on Sunday, too. Sunday is my errand day. The lobby in the PO stays open and I use APC postage for the books. I mark mine mailed on Saturday night, when I wrap them, though.

Believe it or not, there is a post office near my work that is open late (until 7 or 8), the lobby is open overnight, and there is counter service on Sundays.

(ETA - Just checked the website and counter service is 6am - midnight 7 days a week.)

Also, some people print postage online, which you can do 24/7.

I'm usually online once a day, in the morning, and can generally only mail on Friday or Saturday.  I tend to mark books mailed after I mail them, which means usually marking books as mailed on Sunday even though I sent them on Saturday.

thanks for all the possibilities.  I have never seen a PO that offered any services on Sunday, much less access to self-mailing when the counter is closed--even on weekdays-- so obviously there are many more mail hours available in other locales than most of us ever see.  I even use the Tampa International airport PO which has counter service open til midnight, but that's the biggest city PO that  I'm familiar with.

edite to add:   I regularly mail to HI and Guam (even lived in Guam for 2.5 years) so pay attention to day/hour differences.

I have books enroute to me that show they were mailed last Sunday or on Presdent's day (last MON).

Another possibility not mentioned is that the person could have mailed them earlier and not been able to mark them mailed until Sun or Mon.  Maybe mailed them on their way out of town.  The fact that a book was marked mailed on a date does not mean that it was actually mailed on that date.  It could have been earlier as I stated.