I'm not a physicist, I just like physics, so don't blindly believe in what I'm going to say.
I think that the two situations are identical because in both cases: First: The observer alone in deep space, and Second: The observer in free fall, the observer's gravitational field is distributed spherically and symmetrically around each part of he (observer).
To better understand this mechanism, think that if a force is applied to the observer (in deep space) as if attempting to separate the observer from its own gravitational field, in this case the observer notices the effect of this force and the respective acceleration, because in this case the observer remains slightly ahead of the distribution of his gravitational field, which "tries" to accompany he to maintain spherical symmetry.
Therefore when this force ceases the gravitational field returns to have spherical symmetry. This symmetry to which I refer is the distribution of the field of gravity around each particle that makes up the body of the observer.
This is because the body of the observer has local presence, while its gravitational field is infinitely extensive. It is this extension that prevents the immediate reaction of the field.
In the Second case: When the observer is in free fall, his gravitational field is equally distributed spherically and symmetrically around each particle of his body, because the larger field that causes the free fall attracts equaly and simultaneously, the observer and his own extensive field, thus secured the spherical symmetry.
Therefore, the equality between the two situations is justified because in both cases the distribution of the gravitational field, around each respective particle that makes up the observer's body, is symmetrically spherical.
Sorry for my English.