London Cable Car Oystercard Deals?

The London Cable Car Crossing Opens

According to “The Orbit Tower – London Cable Car” and other sources, a single fare across the Thames on the new London Cable Car opening on June 18th will cost £3.20 if you pay by Oystercard Pay-as-you-go.

But they also have a special offer return trip non-stop bargain price of only £6.40!

So it’s exactly twice as much to stay on and ride back and firth once as it is to combine two singe trips with a stroll around the other side, or whatever.

What’s the sense in that?

But more to the point, how do you click in and click out to ensure you are always charged the correct fare?