satisfactory unsatisfactory

[brianmoooore]

You could, but that's getting into the territory of remedial action as opposed to reporting.

Not really. You will be disconnecting to test, so just leave disconnected. There's a perfect example in another current thread, where a (badly) terminated, but still live wire was discovered behind plasterboard in a bathroom.
As for "something critical", I mentioned sewage and water supply pumps, and always report to the property occupier what I've done, with instructions to contact me immediately if something that was working is now found not to be.
One example I remember from some time ago, was that the stairwell lights in the neighbouring property had ceased working after my visit.

 

[Risteard]

Not really. You will be disconnecting to test, so just leave disconnected. There's a perfect example in another current thread, where a (badly) terminated, but still live wire was discovered behind plasterboard in a bathroom.
As for "something critical", I mentioned sewage and water supply pumps, and always report to the property occupier what I've done, with instructions to contact me immediately if something that was working is now found not to be.
One example I remember from some time ago, was that the stairwell lights in the neighbouring property had ceased working after my visit.

I don't generally disconnect anything to test it - an exception perhaps being the humble ring final circuit for ring continuity.