As I understand it..the violin is owned by a non-musician, who allows the musician to use it, as it should be, for a great instrument deserves to be played, and heard. This is a fairly common practice..
I assume it's insured...wonder if the premium is paid by the owner, or possibly the orchestra, or the user?
As compared to, say, a piece of jewelry worth millions, which the policy usually requires be kept is a vault except on the few occasions when it's taken out to be worn, this violin is out and about all the time..planes, taxis, carried on the street..
I think the owner holds the policy, but there may be event coverage by the orchestra, too.