Are aftermarket power cords required to be UL / CE approved?

@rbstehno 
Sorry, I was in the property insurance claims industry for almost 40 years. Although HO policies do have certain exclusions, there is no exclusion for stupidity or carelessness. The average person hiring an electrician would not be well versed in the various wire gauges and would claim ignorance. The claim is paid and the insurance company, hires a cause and origin investigator, documents the cause of the fire and Ins. Co. subrogates against the electrician. The wood stove example is just an example of the homeowner's stupidity, claim is paid and there is to responsible party to subrogate against. All the insured has to say is "gee I didn't know". Of course, permits and inspections as required by local jurisdictions should always be obtained for the homeowner's peace of mind.   

A fire is a fire and HO insurance will cover it. The only way they won't is if you lit the match and started the fire. If the power cord caused it, they will go after the manufacturer for reimbursement (subrogation).   

@8th-note,
I was going to give the kitchen fire example, but you did it perfectly.
With regard to insuring audio equipment, that can vary from company to company. All you have to do is check the section titled ’Limits on Certain Property". Usually jewelry, firearms, etc. will be listed. If audio equipment is not listed, the limit of coverage is the overall policy limit which covers all of your personal property. As mentioned above keep receipts and photos of everything. It great to have a good agent, but remember, they basically sell insurance and usually just have a basic or rudimentary knowledge of specific coverages.
Also, always make sure you have full replacement cost coverage, not just actual cash value (market value).