One thing that smells fishy is that the qml app starts getting touch events even before compiz/unity7. I think that this should not happen as the qml app does not subscribe for ownership events (unlike compiz/unity7) and ownership is offered to compiz/unity7.
So the qml app should only get touch events once compiz/unity7 rejects ownership of the touch sequence, but that's just not happening (qml app was already receiving events from that touch sequence by that time).
One thing that smells fishy is that the qml app starts getting touch events even before compiz/unity7. I think that this should not happen as the qml app does not subscribe for ownership events (unlike compiz/unity7) and ownership is offered to compiz/unity7.
So the qml app should only get touch events once compiz/unity7 rejects ownership of the touch sequence, but that's just not happening (qml app was already receiving events from that touch sequence by that time).