We had silk at the reception and on the decorations in the chapel. We did use real flowers for the bouquets, boutonnieres, and corsages (for tea girls, servers, etc.). The wedding my husband is officiating and our daughter is flower girl in tomorrow has all silk, and it looks fine. I think as long as the silk arrangements are well-done, they are fine. We still have one of the reception bouquets, and it still looks nice.