Actually people cannot tell you, unless it is the trade show people themselves, that you cannot take pictures. It falls under the public view area. I'm an amateur photographer and have done work for newspapers. You can take pictures of the quilts and sell those pictures as they are considered news worthy.
It is a no no however if you take an artistic shot showing only the quilt. You can do an artistic shot with the quilt in it, if the quilt is not the primary point of the shot but has a point in the shot. Same with statues, or stained glass.
Legal photographers handbook is the source.
While copyright protects people I do have to agree, sometimes this is going way beyond the pale and into the ridiculous area.