adr,
What you allude to is indeed part of the security mantra of agregation.
It is the same argument for not publishing publicly collated open source material etc as you are potentially focusing a hostile agent on interesting information.
How many people would be interested in the complete data on 10 people? or a 100 people scattered throughout the UK, or even a 1000.
But given a working population of some 24 millions we are talking 2.5% of the working population. Now even a marketting company would die for that focussed data set.