Trouble is, these days "everybody's a lawyer." Indeed, I recently read of a service change that was followed by a fire, and a lawsuit against the contractor.
While the insurance company paid to get the matter closed, it sure looked like the actual cause was some wiring inside the house. A more cynical person might even say it looked that the occupants were busy rigging up this disaster while the contractor was changing the (exterior mounted) panel.
The whole gist of the claim against the contractor was that he somehow should have known that a dangerous condition existed within the house, and acted to correct it before energising the new service.
Not to be overlooked is that the first inquiry from the lawyers was as to the extent of the contractors' insurance- and not, 'what was the work done?'
These are serious matters- a dysfunctional legal system lets the sharks flourish, while us minnows run for cover!
With this, we return to how a successful business is based on a few good customers. When you have an established relationship, you don't have to worry (as much) about such game-playing.