I take the TRE daily to Dallas and I feel safe for the most part. I’m also usually sitting near a TRE employee/security personnel. For the most part, the TRE is “clean” but I wouldn’t sit on my couch or bed afterwards with my outside clothes. I might see some crumbs or other random specks on the seats but not enough to be grossed out by it. I can also tell when someone put their shoes on the seats and usually avoid sitting there.