Oyster Card: privacy nightmare, UI design disaster or both?

I have recently been to London and used the Oyster Card to pay my Tube journeys. At first glance, the Oyster Card seems to be a great concept: an electronic purse used to pay small amounts. When you get in the Tube you put the card near the sensor and when you get out you put the card near another sensor, and the correct amount is deducted.

However, it has two huge drawbacks:
Privacy concerns:
you fill a form to get a card (even though you can avoid that), and then there is a complete record of every single trip you make, including origin and destination. If you combine that with the fact that there are cameras all around London, Big Brother (the one from the book, not the TV show) comes too close to reality for comfort (no way the TV show will ever be within an AU from reality).
UI Design:
Matt Stephens points an extremely good issue. If you forget to get your card to the exit sensor you get charged the maximum amount. It is understandable that they don't want people to avoid paying by tailgating (or should it be back-gating), but during the rush our you don't have much time to check if the correct amount was deduced. I don't think it would have been to problematic, as Matt Stephens suggests, to install sensors in the exits (damn, the sensors work in toll stations!), or using all the spoofing^H^H^H data collection for something useful. Nope, big fine for you Mr. Cheater!

PS: It is a sad state of affairs that if you look for Big Brother in Google, the book is only the tenth result.