I have reviewed several contracts recently for event space. Its been common for people having the events to want to see language that doesn’t give the event location an out if they are short staffed because of Covid. But at the same time, they want to be able to cancel (with a full refund) if the turnout for the event is less than desired. To me its only reasonable to have the outs be mutual. If one side only gets out if performance is unlawful or impossible, the other side should have the same out.
In terms of the camp, if one or two campers test positive refunds may work. But if half the kids test positive, can they afford to refund for 1/2 the campers? They already incurred pretty much all of the costs. Maybe some food could be canceled but depending on timing they may be on the hook for that too. What is the event host supposed to do in those circumstances?