It's really important to understand what is covered and what isn't when buying any insurance. So that you can weigh the pluses and minuses, and to know what you need (and don't need) to buy. Nobody likes buying insurance because it is expensive and you probably won't need it, but it can come in handy when you do need it.
I just took a look at the insurance we purchased from Travel Guard (Silver Policy) before our trip to the Caymans in Oct/Nov. Below are screen shots summarizing the coverage and information about the travel cancellation policy, and I believe that we would have been covered, for the amount/items insured, if we had to cancel due to a medical emergency like
@Kharon.
We paid $320 to cover both of us with this policy and my comment about "for the amounts/items insured" is an important factor when picking travel insurance. I am no expert but I do try to review the coverage, ask questions, and make an informed decision. I have never had to put it to the test (fortunately!) but I hope that I've gotten it right.
I used the total cost of our lodgings on Grand Cayman and at our all-inclusive resort/dive package on Cayman Brac as the basis for the coverage needed, because those were the big ticket expenses. I did NOT include airfares because we used our credit card air miles to pay for our airfares, so that would have increased the insurance costs if included. I also did NOT include car rental insurance, because our credit card covers most of the car rental insurance and we only needed to buy liability insurance from the rental car agent.
We also did not pay extra for "adventure sport" insurance because scuba accidents are covered under the main policy and we also take the mid-level DAN dive insurance.
But I did add upgrade coverage for "emergency evacuation and repatriation" for an extra charge because that is important to us. It's great to transport us to the nearest hospital for emergency care, but I want to decide where we go for treatment after we are stabilized.
I have a non-diver friend who was in a bad car accident with his family on vacation. They were traveling in the South Pacific and needed helicopter transport to an emergency medical center. After they were stabilized the costs of flying his family back home was very high. His wife and daughter had been badly injured and each needed a full row of seats in the airplane to lie prone during the long trip back. So now I try to plan for "after the injury/illness" and think about the trip home and getting to a medical center of our choice.
We always designate family members as individuals able to make decisions for us if we are not capable - and we give them a copy of the insurance policy and itinerary before we leave town.
Another important factor is to buy the insurance quickly (within 2 weeks) after you book your trip, because rates will be lower and more coverage options are likely to be available. When you get nearer to the departure date the rates go up and the options become more limited because the insurance company figures "something must be going on with this guy!" if you are suddenly looking for insurance close to the date of departure.
Trip insurance may be a waste of money, but I hope not. I feel better knowing that we have some protection. Everybody has to make their own best decision.