Don't congratulate yourself too much. It's called the tidal force, and scientists and sailors are aware of it.
Einstein's example was for a uniform (i.e. divergence-free) gravitational field. In principle, you can create a uniform field by constructing a large, flat, massive sheet; near the center of the sheet, the field will be uniform. Or, you can achieve an arbitrary uniformity it by examining a sufficiently small volume of space.
The point of the equivalence principle is not that it isn't possible in practice to tell whether you're on the surface of a planet, but that accelerations and gravitational fields are physically the same phenomenon. That's a pretty radical notion.
Ice is cold and hard while steam is hot and gasseous, but that doesn't alter the fact that they are fundamentally the same stuff.