How to hotels assign rooms to reservations? Is there an order - is it just sequential, or totally random?

I am asking because it would seem I always get assigned a room where there are always people staying in the rooms next to me. I always put on my reservation that I am a real loud snorer. I would think that they would try and put guests in rooms as spread out as possible to increase the sense of quietness. For instance I am staying in a hotel tonight, just for one night. I am positive the hotel is pretty dead - the receptionist as much as said so. Yet it seems like everyone on this floor is crowded around one little area.