I recently attended "Quilts From Holland" show where there were signs posted "Please do not use the camera flash". I asked about this and was told that numerous flashes could damage the quilts. I have never heard of this before and have attended many quilts shows. Has anyone else come across this?

It is unlikely that the fabric would be damaged in a short period of time, but it is true that light can damage fabric and colors. Think about the museum displays of dresses (First Ladies Inaugural Gowns, Famous Wedding Dresses, etc) that are in very dimly lit displays.

That's plain silly. These quilts are shown for a short time. It's not like they'll be on display for 10 years....

This is quite common in museums. Not now, but the bright flash used to be the result of special chemicals that would be put into the air as a result of the flash. I don't know if the current prohibition is a leftover from those days, or if there is something else. It is quite a bright flash. Why take the chance? Most cameras take good pictures without a flash.

In a quilt show setting, it is likely that a large number of flash photos would be taken. Yes, lots of high intensity light will fade fabric.

And these quilts are on loan from their makers/owners. The quilt show is right to take the best care of them possible.
Most quilt shows are in rooms with lots of light, and most digital cameras will take a very good picture without a flash if you use the right setting.

You can't take pictures in the Smithsonians either. (Unless the rules have changed there)

My camera usually takes excellent pictures without flash.