What this lady should have taken out is an insurance policy for stupidity, legally known as "errors and omissions" insurance.
If you participate in this current "gottcha", no prisioners type environment, you can't reliably go thru life as a DOPE. Tees crossed, I's dotted. That's the way life today is folks. Otherwise the machine will flatten you.
Pay attention to the fine print as just mentioned. The fine print has the same legality as the big print. If you read that if you do X you may have a problem, take it as a FACT. If you rent from Alamo/National in the USA for example, and if it's a "luxury" which is hardly that, your spouse cannot be added as an additional driver. Makes no sense. But that's the contract you are signing so don't be shocked if things go upside down if the wife has an accident. Don't assume your regular insurer will step up.