For the record, I do not know what it is in my luggage that is causing the requirememnt for manual searches. I can only guess.
I live and work overseas and frequently bring things from the US to my colleagues so that they can share in some typical american experiences (like Thanksgiving pumpkin pie).
I do pack so that the items are at the top of the luggage and yet the luggage is still all trashed when reassembled.
I have searched the TSA website to find out information about being present when they search my luggage and cannot find anything. I was hoing for some insight here from experts. I was not looking for a comment like don't bring those items, especially when I don't know what those items are.
Lesson learned. Don't ask for assistance here.