Some very interesting points and perspectives here.
I agree the large Bobwhites wouldn't do well. Stealth and flght are
a quails only defense. Bobwhites do neither well.
The few Coturnix that we have around our house are escapees. We
have recovered at least 50% of them, usually by chance or we hear them.
Coturnix are not native so the impact on local birds is a possible concern
but it's more likely they will be eaten by our local birds.
Most gamebirds are raised for hunting. A truck will literally drop a few
thousand at a hunting club and they will be used for dog training and
target practice. Many hunters I have talked to don't even "bother" to
eat them. Draw your own conclusions on this one. I am not bashing
hunters. We raise dozens of Coturnix and eat them. I would not be
against releasing our extras, hunting them, and then eating them.
It's sorta a dual purpose thing.