They can't offer if there are no spare seats in the requested area.Seems as if people are being offered tickets randomly and not in the area they asked for.
Dont know how hard it is for the ticket office to accommodate people in the stands they asked for but reading through the thread it hasn’t happened too often.
Think someone posted before about a thread for people wanting to swap into areas that they wanted. Can’t see anything looking through the forum though, but this could be a decent idea. Think you have to pay £20 for a name change.