You’re probably referring to something like this: https://www.diversalertnetwork.org/insurance/

Even when it comes to plans purchased via association membership, those seeking insurance should scrutinize the policies to make sure that the coverage desired is the coverage delivered and the insuring party has a good reputation and financial standing so as to assist in the way the customer wants/expects assistance.

I have bought travel insurance from GeoBlue which is a Blue Cross company for a number of years. Two years ago I had a double hip replacement surgery and was worried about whether that preexisting condition would affect that insurance. If you look at the policy provisions you will see that it does not exclude preexisting conditions. The policy I buy is an annual policy and only cost around $225 for a 63 year old. They also sell single trip policies.

You may also want to look at an evacuation service such as MedjetAssist: https://medjetassist.com/medjetassist