[Physicist]

The two observers won't agree on whether there is or is not a magnetic field in your example, this is true, yet we both know that the field does exist! It just isn't *observable* to one of the participants.

By that standard, the field always exists, everywhere. Zero is a perfectly good value for the field to have, as you point out. So if you want to say that a zero-field region of space is not a field-free region of space, I'll accept that.

Now, show me a region of space that is free from all gravitational fields.

[Old Professer]

Now you're back to the static state.