Just came across the new Square card reader design. Since the reader head has to be able to move around in the casing for optimal friction, and to assemble the whole thing with a P&P machine, Dorogusker used a flex PCB to mount everything. But this also meant he could implement test points on an extra piece of flex that can be cut of after production and testing.
Genius! This way you can save a nice amount of PCB real-estate and have a slightly larger and easy to handle test jig.
Flex without components mounted and test point part cut off:
Flex and components mounted in enclosure:
Now I just need an excuse to design some flex PCBs.