Obviously they can, but I feel like because we are having our wedding outside and not in a church people are thinking they can just wear jeans or something not as formal. Our venue is extremely nice, reception will be in the same location but a really nice log cabin type building. My future father in law doesnt want to wear a tux, and I think he feels that way because it will be outside. The wedding is June 1st, in Michigan so it probably wont be that hot outside anyways...I just feel troubled by this..help?!