No, she was in that state and subject to that state’s laws.
I suspect that it might be legally questionable to quarantine someone who has tested negative, thereby prohibiting him or her from traveling to another state.
As long as this kind of travel takes place on non-public transport, I am okay with this policy.
Of course, the first time that someone like this becomes infected after transport, there will be new demands for quarantines in that person’s home state.
It is probably reasonable to assume that many states will follow NY and NJ’s lead. And THAT is why Obama is so concerned about their policies.