How will this even be implemented at the gate?

Take this scenario:

Pax starts in KUL, connects through DXB on the way to JFK. Checked-in luggage, but for whatever reason still has an iPad/Laptop on them for the KUL-DXB flight.

At the gate in DXB headed to JFK, assuming they do gate screening, where does the offending device go? Unless every single outstation prevents the devices on connecting flights too, I can see this being a larger problems for travelers at the connecting point.