As far as inspections go in my town I have had a cat on my truck twice during inspections. Two different trucks because they got inspected at purchase. I've been driving since 1996. Gas and diesel. No issues with being cited or failing a inspection. A tech might be abe to tell. A inspection place? I doubt they would do that. Law enforcement? Again very doubtful unless they had some sting. I could run a camera down my tail pipe if I really wanted to just like we do for problem drains and prove it was gone as well.