My sister had a destination wedding, and none of her family was invited, as a matter of fact. She was married in Las Vegas. None of us three sibs were invited. She originally was going to get married about four years before, in October of the year in which our mom died. She actually had invited me to be matron of honor. Since mom died, she cancelled the wedding, which I can understand. She was living with her fiance at the time, and had been since shortly after our dad died, which was about 18 mos before the wedding was originally scheduled. Fine, if I'm not going to the wedding, I'm not sending a gift. I sent her a small gift, actually, a wedding clock from Lenox.
Some people are really obnoxious about weddings, though. One of my husband's coworkers, his boss at the time, got married at Las Vegas. Then, a few months later, they had a big reception at a hall in their hometown. We were invited, and my husband felt compelled to attend, and bring a gift. They showed a video of the ceremony. The problem was that it was the middle of winter, there was ice covering the roads, and, it was my birthday, besides. I would have been fine with delaying my birthday dinner for better road conditions, but, actually, all things being equal, I would have wanted to skip the reception, also. There is just something not nice about not inviting people to the ceremony and then throwing a big shindig later, to get gifts from coworkers, etc. Having a party at home for family and close friends, that's OK. Even then, if I were a family member, I would feel a little left out about not being invited to the ceremony. Makes me feel like an afterthought.