You seem to be under the impression that booking.com provides property management services. I'm not aware of them doing any such thing, but if they do them she should absolutely raise a dispute under her contract for those services. A quick scan of their information page for property owners is pretty clear, though, that it's the property owners' responsibility to get insurance if they need it (they even have some partner links for insurance providers.)

Using booking.com to advertise and resell her business does not change the fact that managing that business is entirely on her. If she doesn’t want to put in the minimum effort, or expense (e.g. insurance) required, she should get out of the business of property letting.

You can hate booking.com for many reasons, but "not running my spare property as a hotel for me so I can just sit back and count the cash" isn't really one of them.

Booking dot com aren't buying homes that families could live in are they? Booking dot com are just facilitating bitch face making money on a human right. Systemic change is required:

• banning people owning more than 1 or maybe 2 homes
• taxing property earning at 90%
• no tax deductions for property costs
• building more government (fed, state and council) owned social housing
• short term rentals susceptible to same rules as hotels
• short term rentals requiring council approval

The game is rigged but we shouldn't give a pussy pass to the players just because they can play. They should be shunned and labelled as traitors to society.