We have used Clarion -
Clarion Associates, Inc.| Insurance Firm dedicated to Musicians
I would suggest comparing their rates to a homeowner's rider if you are only insuring one instrument and do not need some of the extra coverage I mentioned.
In addition to those violadad mentioned specifically, I believe National Flute Association members also qualify for reduced premiums with Clarion. If your daughter is not already an NFA member, she really should be and, if you do insure with Clarion, the savings in insurance costs alone may more than repay the cost of the dues