You may well be right I certainly agree with what you have stated. However the case you have quoted the house owner was acting perfectly legally and entirely within building regs notification requirements. While I also agree that was an overstatement and maybe should have read, ...may have insurance implications... I will be more careful of my wording in future.
However I do have some reservations regards your statement in that it may suggest to a wider audience reading this thread that even if you do, or someone does negligent electrical work it is ok as insurance will pay out. Personally I would not take that as a given fact. I would tend to more suggest to err on the side of caution and at least consider or consult with the insurance company prior to say as a plumber, undertaking electrical work. The legal underpinnings of the regulations and statute around electrical work are somewhat complex and lack of compliance to the aforementioned can be a legal minefield.