I don't condone hands free when your vehicle does not have it. But Ford's resistance-based system sucks. I get I have leather steering wheel, but they could have a combination of resistance and thermal sensors to detect my hand is actually on it.
I have a few straight roads and my wheels are well aligned. Even with BOTH hands on the wheel if there is no "input" the system will still warn you in normal "lade departure" mode.
If you activate the cruse-control, the way ford tries to ensure you're paying attention is pre-programmed to "drift right". It's a few degrees of right turn, just enough that it seems to "pull you" into the line, but as
@dlcorbett mentioned, the weight on the left side of the wheel (or water bottle) count balances the drift. Until the wheel tries to turn left, then you will oversteer.
In my book this lane guidance goes down as a solution to a problem that shouldn't exist. If you're a decent half paying attention driver, why do you need the car to "guide" you in the lane? The only time I've ever seen it be "useful" is when a driver IS NOT paying attention or to enable them to check their phone or something. #ManualTransmissionsReduceTextingAndDriving.