Regarding my previous post on Bruce Schneiers' blog... the discussion there continues and it is great; For the record, I replied again after it evolved, see below (but please read the whole thing)
Ok, my reply:
This is exactly the sort of discussion I was hoping for.
Regarding your comments, Bethan; When someone's data or observed behaviour (which is also data) is captured, that person (data subject, thanks for coining), has something to lose. He could for instance be exposed, embarrassed, harassed or whatever, by ill-meaning data-capturers. This is an acknowledged form of harm to individuals, against which laws are instated in many countries.
Individuals themselves are also aware of the risks of being 'observed' or 'captured', and commonly display a degree of consciousness and responsibility regarding their (chance of) exposure. Close the curtains, protect privacy. Maintaining a degree of privacy is common, and not only for those who have something to hide.
Surveillance, spying, or otherwise secretly observing or recording peoples behaviour (physical or otherwise) is usually not allowed as Clive pointed out; (interesting exception: government or police).
For me, I'm not concerned with the data capturing activity, legal as it might be, but with the subsequent _uses_ of the data about the data subjects. Here you claim that data subjects can not expect you to limit your use of their representations. This I find disturbing. There is, again as Clive pointed out, a certain expectation of intended use. Unfortunately, there is often no way for the data subjects to prevent deviation from those expectations (which I find even more disturbing). This lack of control for the data subjects is (for me) an area of great interest/concern (which I try to elaborate at http://egosphere.blogspot.com )
The situation you describe, where a persons data, once captured, could be put to any use that would benefit the capturer, seems to me exactly the thing that most people would like to protect themselves from, if they could.
Lacking any control over your representation (its correctness, storage, distribution or exposure), even when it was once willingly conveyed to some organization (such as your energy company) makes you dependent on _their_ willingness and ability to change your relation with them. You might become powerless to influence their behaviour, since their representation of you, once acquired, is the truth for them. Never mind the 'unintended uses' that might occur (see http://datalossdb.org/ for plenty of examples).