No idea, but Mack is seen without his trailer several times throughout the Cars franchise.
The Cars world is suspiciously full of various pieces of infrastructure that are all in remarkably good condition considering it’s a planet allegedly populated only by machines that haven’t got hands. Perhaps trailers, traffic lights, signposts, etc. are all just some manner of specialized plants or fungus that pop out of the ground that way.
What? Why are you all looking at me like that?






And if you moderate a community you can just click (in the default web UI, anyway) “view votes” to see whodunnit. You don’t even need an external tool. It’s good for finding downvote brigade people and so forth.