Perhaps, but what did occur on every system was the most horrifically jarring texture popping. Looking away from a surface and then looking back (without changing position) was enough to flush the texture and have it reloaded so it takes a second or two to hit maximum resolution. That is a terrible way to handle texturing.
Our eyes are most sensitive to motion. Geometry-pop is bad because a few pixels change in a way that is inconsistent with the model. Texture-pop means that lots of pixels change in a way that is inconsistent with the model - the motion does not map onto motion in the virtual world. This is the worst possible choice for immersion and it completely ruined Rage.
Megatexturing is really just a big exercise in caching. The optimisation problem is to not to minimise distortion in the projected image (i.e maximise the resolution of each texture on each frame), the problem is to minimise change in the projected image. This implies that if somebody walks closer to an object then the transition of textures should be as smooth as possible.
In summary, the idea behind megatexturing is cool (unique textures everywhere), but the implementation of it in Rage is just about the worst possible.