There are outfits that will run a camera down the line and give you a DVD on the interior of the line to look at.
People that work on main lines, don't use hand snakes.
That equipement will have a large barrel for the cable and the cutter will either be a 3" or 4" for cutting roots.
There are products for killing invading tree roots.
All in all, he does seem to have a scary story though.
I wonder how often that one works.