Essentially, that would require a third party medical practitioner to determine whether or not West's exhaustion would physically allow him to continue. But it also would typically come with exclusions: for instance, if the exhaustion was due to drug use, sexually-transmitted diseases, "unreasonable or capricious behavior" -- which would include cancellations as a result of excessive partying or similar behavior -- and whether there was a pre-existing condition, meaning if the person had a history of exhaustion or a previously-diagnosed and undisclosed illness.
A fairly textbook example of a situation that would be covered by this type of policy is Lady Gaga's 2013 Born This Way Ball Tour. With 22 dates to go on the trek, Gaga suffered a labral tear in her right hip that required surgery, forcing her to cancel the remaining shows on the tour and causing $25 million worth of ticket refunds. Gaga's injury clearly would have been covered by this type of insurance, including expenses related to shutting down the tour, advertising costs and lost revenues for both the promoter and performer.
Again, however, West's situation is slightly different, and there is no clear answer.
"[The policy] is often invoked very quickly for specific injury or illness that is diagnosed easily," says Paul Bassman, president/CEO of Ascend Insurance Brokerage, one of the top insurance firms in the music industry. "Exhaustion would definitely be harder to prove, but I wouldn't say it's impossible."
Live Nation, the promoter for the Saint Pablo Tour, likely has its own policy, which generally differs from an artist's policy by not carrying exclusions for things like drug use, capricious behavior or other situations, though the independent medical evaluation would still be required. That could leave open a situation where Live Nation would be covered for its own expenses, including its guarantees to West (if they are responsible for paying those guarantees in the event of a cancellation), while if West's condition was not deemed to be covered by his insurance policy, he may still be on the hook.
For now there is little to do but hope that West is getting the treatment he requires, while any definitive judgment is too early to assess. "We just don't know enough about why he canceled," Bassman adds. "Until more information is available on the specifics of the cancellation, it's not possible to determine whether this will be covered by insurance or not."