A dApp that creates a new account and transfers EOS to that account will have to 'pay' for 240 bytes of RAM for the new balance object on the new account. When the new account transfers some funds, 128 bytes are returned to the creator dApp. How can the creator dApp reclaim the rest? Or alternatively how can the creator have all the RAM billed to the receiver?
It isn't possible to get the RAM back for the new balance object, and it is something you would have to factor in to the cost of creating accounts on the network.
It also isn't possible to bill the receiver for RAM, as this would allow anyone to use up anyone else's RAM.
I know that Block One are working on allowing receivers to pay for CPU and NET usage, so perhaps we could expect an update on this at some point, but I don't know.