Dude, a mediocre violin starts at about $25,000.
And a good bassoon starts at about $35,000.
They ain't taking their good instruments outdoors anywhere in England at any time of year.
Maybe in the deserts of Australia, on a cool night. MAYBE.
Even Southern California, at the Hollywood Bowl, is too humid most of the year to dare bring a really nice instrument [especially at night - and I wouldn't want Southern California UV radiation burning through on a really nice instrument during the middle of a summer afternoon].