I was at the Post Office yesterday mailing PBS books. The cashier's computer popped up a message. Something like "Your package has been randomly selected....." It asked the cashier to open the package in front of me and she should write down what she finds in my package.

Obviously this has never happened to me and it had never happened at this Post Office before. She was totally "flummoxed"!  I told her go ahead. I don't care, but she was going to have to use her own tape to fix it. Ha ha.... (Well other than the fact I was already late for work, but that was my fault.)

Weird! It is good if they start inspecting more packages, there is a ton of abuse of the media mail system, but annoying that it makes them hold up the line like that. 

It's been a while but in past few years I have received book packages with PO markings telling me the package had been opened and inspected. It's quite rare, but does happen. 

That happened to me one time last summer.  The postal worker did not open the package -- he could tell from the package that it was definitely a book and just sent it through.