I've been on tour for the last few months and have been flying with my PB a lot (just in the US). I've always had to take it out at the airport, but have never been asked to open or demonstrate that it works. The process hasn't bothered me, and nobody has manhandled my PB (luckily nobody else usually touches it, I put it in the tray and take it out at the other end). I just like to make sure that the PB goes through the machine last so I can be there at the other end when it comes out!
My other travel experience, that I was asking for advice on a few months ago before I left, was how to transport my printer on a plane. It's a Canon i70 mobile printer. Most posters encouraged me to take out the ink in case the pressure caused it to leak. I was not really looking forward to this whole process, but it went better than I thought. Here's what I did:
The box was too big to bother carrying around, so I put the printer itself in the main compartment of my suitcase, between layers of clothes so it would be cushioned, and stowed all the cables in a zippered compartment where I kept all my computer cables, phone charger, etc. I took out the ink and put on the orange caps that cover the hole where the ink comes out. I put them in a double ziplock bag, along with my unopened spare ink, and put that bag in the compartment with the cables (trusting that the two layers of ziplock would protect my clothes in the event of a leakage

) I never had any problems with it or signs of damage or leakage. In fact, somewhat to my surprise, I was able to put the ink back in the printer and continue using it, with no noticable effects. That was my biggest concern, having to replace two barely-used ink tanks once a week.
Hope that helps some future travellers!
