A cautionary tale. A friend booked to go to Disneyland Paris on the Eurostar during the recent bad weather. Eurostar's website advised passengers to travel only if necessary, due to trains having been stuck in the tunnel. They also warned of further cancellations and major delays. Since she was travelling with a small child, she cancelled the trip.
She had taken out Disneyland's own insurance at time of booking. It is not possible to see full policy details on the Disneyland website (there is a brief version in their brochure), and also you must book the insurance at the time of booking your acommodation. The insurance details were not emailed through to her at time of booking, even though they were supposed to be.
After cancelling, she read the details of the policy. It was not only very expensive, but had many exclusions. For instance, deaths of close relatives were not covered unless the person who died was actually named on the booking. The policy, covering only 4 days, was also very expensive, perhaps four times as expensive as regular travel insurance.
The moral is, first if buying a Disney insurance policy, check it BEFORE bookiing and make sure you can't get a better deal elsewhere.
Secondly, don't cancel just because the train operator advises against travel. Regular insurance policies don't insure against this either, unless the specific train you were going to use, is cancelled. Bad weather and adverse advice from travel companies is not a reason for cancelling.