In my experience, the wee statement thing just helps them decide who to put you with, rather than where to put you. For example, I wrote that I was a quiet person and wanted to live in a quiet area but in Rootes. As it turned out, I was put with some very quiet people (who I didn't get on with, but oh well...) and was indeed in Rootes. I believe some areas of Rootes (Draycot and Gibbet houses if anyone is interested) are designated as 'quiet' areas - so for example during the exams we had to be very quiet to make sure we didn't disturb people.
As an extra note, I think most people who put Rootes down as their first choice get it - it's so big I think they can easily cater for everyone who wants to be there.