I'm not talking about Emirates. I only used IAH to DXB via Atlanta with flight #8 as an example because one airline has that.
"They" in this context is any U.S. air carrier that does a domestic flight continuing into an international flight with the same number, but different everything else.
Forget Emirates and Houston.
Continental 90 from LAX-EWR-TLV.
Delta 72 from ATL-JFK-IST.
etc.
What is the purpose of labeling the domestic leg the same number as the international flight? Marketing? You still can't advertise nonstop service or direct service just with the same flight number though.
It is just strange to me to be standing at the gate and hear them say "withing continuing service to ____ [some far away land]" and nobody in the gate area is even going there.
A guy I flew with a few weeks ago worked in network and route planning at a large airline for a bit...I bet he knows this. I'm going to ask next time I see him.