I fly to/from York from TX (to BWI). Always with carry on bags. I pack very sparingly to allow lots of room for the return trip. I take stuff out of the boxes and flatten them. I bring lots of bubble wrap with me. I wrap each item to protect against banging around (skidmarks out!) and have never had an issue from TSA. No questions, no looks, no inspections.
Now, I will mention that one time I was flying home from Wisconsin after attending an airplane building workshop. I had corded drills, files, crimping & flanging pliers etc. in my checked luggage. They never questioned the contents, but I *did* see an agent carrying an X-Ray of my bag into a TSA office (it was a VERY small airport - 3 gates, and we were the only flight, so it was easy to see things). I figured they were going to use it for training purposes. No "we searched your bag" tag inside the bag when we got home.