When I was in Italy, the two Hiltons I stayed were quite simple for breakfast. Just walk into the area, they ask you your room number and sit you down.

I think it depends on the property though. In my most recent stay at a Doubletree, they gave us two vouchers. Just present them when you go to be seated and that's all. I have my My Way set for breakfast, but at that DT they actually asked me if I wanted the points or breakfast. So even if you don't have it set, some may ask you.