large backpacks and daypacks

i am pretty sure that anyone who owns a large backpack, invariably, also has a day pack around especially when traveling. i have often seen folks at the airport bearing large packs with a day pack strung over their shoulders from the front, which kept falling off. this gave me an idea. i made a working prototype and it is very simple and works because i still use mine. i would just like to ask how many notice this problem and would be interested in seeing an inexpensive gadget on the market one day.i am in the process of having it developed as i write this, but wanted to find out what others think about this idea. thank you very much for your time.

If you're describing what I think you're describing, it already exists. There are front pockets and pouches that attach to the harness of a backpack, as well as the Aarn bodypacks - which have two front packs that double as a separate daypack when you remove them from the pack harness.

what i have in mind is something can attach ANY small pack to a larger one. a universal attachment system

four small pieces of 550 cord?