I think it is supposed to be a security apparatus to keep someone from stealing the Cats off of it. The thing is they'll steal the apparatus also if they cut front and back.
Erampu....theft of factory Catalytic Converters happen quite often. One evening in Springfield, Ohio, over 100 CC's were stolen off of cars. Cordless Sawzalls are a thief's best friend. Now the Recycling places have to have a picture ID and keep a log as to what comes in. Catalytic converters, copper plumbing, and an over abundance of wire, throws up a red flag almost every time.