For the 5 years before working with Airbnb I was never exposed to guest cancelation for any reason. My rental agreements referred guests to travel insurance carriers and let them know it was their responsibility to buy it if they wished to avoid cancelation loss expenses.
Since then Airbnb's policy has lead to 2 cancellations for health reasons causing me to diversify-spread my risk by signing up with additional vacation rental sites and using the iCal feature to keep calendars synchonized.
I think it's unfortunate for Airbnb, hosts and guests that Airbnb resolution center will refund guests for illnesses since 1) Airbnb recommends travel insurance 2) Guests are not required to disclose any medical conditions to hosts prior to booking 3) hosts like myself recommend to guests at the time of booking and give them three travel insurance company referrals - giving guests plenty of time to get travel insurance sometimes even after they discover they can't travel and before check in.
https://www.airbnb.com/help/article/241/i-m-a-guest--what-are-some-safety-tips-i-can-follow
Prepare for the unexpected
...For any trip, think about signing up for traveler's insurance. Airbnb doesn't offer travelers insurance for guests, but traveler's insurance is a relatively affordable option that can protect you in case of an injury or emergency on a trip. Some policies even cover lost baggage and travel delays. Check with your local insurance provider for details on your options....
Excerpt from my House Manual sent to the guest immediately upon booking:
Travel Insurance
Just a friendly reminder that if you haven't already considered Travel Insurance, this might be a good time to consider it. Travel insurance is insurance designed to cover the costs and losses and reduce the risk associated with unexpected events incurred while traveling. It is a useful protection for those traveling domestically or abroad. Here are a few carriers.
Alliance Travel Insurance
Insure My Trip
Travel Guard
You can find more Insurance Carriers on your own
Hotel Chains by size in descending order.
None of them are absorbing the cost of travel insurance:
#1 Windyham - biggest hotel chain in the world
Offers their own vacation rental travel insurance - at guest's expense
https://www.wyndhamvacationrentals.com/vacation-rentals/vacation-rental-insurance
#2
Choice Hotels
Doesn't offer travel insurance
#3 Marriott
Offers LIMITED travel insurance in conjunction with Citicards - essentially-effectively at guest's expense
https://creditcards.chase.com/marriott/cardmember/premier_benefits/protection
Airbnb offer's travel insurance - they volunteer their hosts to bear the risk!
The simplest way to handle this is to explain travel insurance up front - prior to booking and let guests know it's their responsbility to purchase it or guests will be taking the risk themselves.
This part of the Airbnb - Host relationship is 100% unfair and unprofessional. Hosts are not Insurance companies. This policy is not customary.
Airbnb has refunded 2 of my bookings in the past 3 months due to pregnancy and death in the family. This is what travel insurance is for.