Do we Trust Ken with our Data?

I came across an interesting post that mentioned Mr Livingstone's favourite play thing.

The government is systematically trying to monitor our every movement. 'Red Ken' is currently using his Oyster Card scheme to register every person who uses public transport, not just in London but in the entire in the South East of England (I should imagine most of them) where half the population lives.

Is this really what Oyster is about? Should we trust even the best intentioned politician, (let alone Red Ken) with this kind of data?