My FI and I are planning on doing one very small cake for cutting, but serving all the guests sheet cake. My mom has (nicely) asked that she get a piece of the actual wedding cake. Are there any rules about who gets a piece of the actual wedding cake? We're on a budget and having a large tiered cake isn't important to us. Can it just be big enough for us and our parents or us and our grandparents and then everyone else gets sheet cake? or are there rules that the wedding party and siblings should get a piece of the actual cake too?