I did the same thing... asked for a quilt back for a show. My daughter was excited about her quilt being shown and paid for expedited shipment plus insurance to get it back to me. It won first prize as the best of wall art (it was Monet's Garden in water-color 1" squares). It's a real compliment to a person for them to know that you think their quilt is special enough to be shown.
Anyway, all they can say is "no" or "I'd rather not". You could be nicer and even offer to pay for the shipping. :oops: