This past weekend, I took TX Sector to the Canadian Championships. I was asked by many people about the experience.
Going from the US to Canada went smoothly. The guard asked my purpose, and I said we were going for a pinball tournament. When asked if we had anything besides our clothes, the answer was “a pinball machine for use in the tournament.” He asked if we were bringing it back, and I answered “Yes”. And we were on our way.
Coming back into the US was a little more difficult. We answered the questions pretty much the same way - “We have a pinball machine that we brought with us for use in the tournament.” The US Guard asked if we would roll down the window so she could look in (of course, that window is broken 
) She didn’t press the issue, and sent us on our way. Maybe it was already noted by the Canadian side that I had brought a game in with me.
Transporting the game, I went with the tie down strap method of transport with a blanket. I figured plastic wrapping it might bring more questioning.
But overall, the experience wasn’t too terrible.