Originally Posted by
stewlevine
this may be worth it in the event some or all of us get sick before the trip, requiring us to cancel.
Then you contact your travel insurance for reimbursement.
Normally you don't buy a much higher priced semi-flexible ticket just because there is a risk of a group member becoming sick (unless one or more in the group has a much higher risk of getting sick). By the cheapest available fare and hope for the best/no sickness.