I was born in Hong Kong and am holding HKID & the China Home-Return Card.

And I am an US citizen using my US passport to travel elsewhere. I never needed a visa on my US passport to enter China since I used my Home-Return Card. If I travel from SheKou Pier to HKIA for my outbound flight, when I check in at the SkeKou counter, would they challenge me as I don't have a visa stamped on my US passport to enter China? I plan to use my Home-Return card to go thru China Immigration for exiting China.