In the USA, our copyright laws (Title 17 USC) define a handful of categories and conditions that must be met, in advance, for any work to become a "work for hire". Hiring a wedding photographer doesn't meet those categories and conditions. In 1976 Congress wrote Title 17 in part to prevent the wholesale abuse of work for hire by publishers and others who routinely assign or commission photography. Maybe there should be an exception for consumers and, if so, maybe someone will lobby for that.