Doesn't seem to work. If I do that and put Warp on the layer, it doesn't render the warp for some reason. If I put Warp on the Canvas, then when the screen scrolls it looks all fast-warpy anyway. If I stick the canvas on the same layer, and tell it to always set to ScrollX/ScrollY then it doesn't render the warp while the screen scrolls.
Argh, I'm thinking there's no way do the Warp while scrolling without getting that speed-up effect