I think it's possble (But can't be done with bare hands).
Focus MK3 sold in my country comes without "Auto" door locking
due to vehicle regulations reason.
But i know if i have the software and hardware to
tweak with BCM(Or GEM? I'm not sure) It is possble to bring "Auto" door locking back.
(Actually, i knew someone is providing this service in my country, dealership can't do this for me(Possible,but can't do) because it will violate vehicle regulations)
So... I think it's possible to disable the "Auto" door locking.
Maybe you should ask someone who have the software and hardware and willing to tweak BCM(Or GEM? I'm not sure) for you
or just ask dealership to do it for you (They have the software and hardware required, and i believe it will not violate vehicle regulations in US, small payment may required).
About the software and hardware, I think it should be IDS and VCM
(Infact, there are lots of hidden options which can be enable or disable,Some of them requires additional hardware installed eg:Windshield Wiper System Washer Fluid Level Sensor which is required to enable washer fluild level low warning)