Nope, don’t believe it. I lived there a long time and the one that got the gold mine still does. My oldest brother is a retired TN cop.
Well you can believe what you want but that's the law currently... I am a Active TN POST certified Reserve Deputy here.
Tennessee DUI law requires that all I need to do is prove beyond a reasonable doubt that you were, operating or in physical control of a motor vehicle on any public road, highway, alley, parking lot, or any other premises generally frequented by the public while under the influence of alcohol or drugs and your blood alcohol content of .08% or higher. Tennessee DUI law defines a person as being legally under the influence "per se" if their blood alcohol level is .08% or higher. This is true even if there is no evidence that the person's ability to drive is actually impaired.
Tennessee also has a law where a passenger can be charged with DUI if they are the owner of the vehicle, they are impaired and they allow an impaired driver to operate the vehicle which they own.
You can believe what you want, but you are incorrect here. TN law just like most other state laws do not require an officer to personally witness a driver physically operate the vehicle, how else would you be able to arrest a "suspected" DUI driver at the scene of an accident?
You do it based upon witnesses, physical evidence and articulable facts you can show in court.