One of the points to come out of the UK branch visit today was that in the latest YB there is a picture of Sam Herd doing the carts. He is showing a person a video on dub.dork. It was stressed by the speaker that this is how the GB want the work done - i.e. leave the literature on the cart until it is clear that a person is interested. So engage with them first and qualify the giveaway.
So they are looking to give less and less away whilst uping the number of hours that publishers do since they can be on the carts for ages.