android:clipChildren="false" allows each child to draw outside of its own bounds, within the parent. It doesn’t allow children to draw outside of the parent itself. For that you would need to set android:clipChildren="false" on the grandparent (as well).
I think what you’re seeing with the colors is just because colors have no inherent bounds. If there is nothing clipping them, colors go forever. My theory is that if you used, say, a stretched 1×1 px image instead of a color, things would be different.