no question "Do YOu Realize" is a ripoff -- they used the non-sung melody of Mind Games and added words, and the orchestration and chord progressins are identical.
if you need further proof, Flaming Lips used to perform Mind Games in their shows in 1992:
the interesting thing here is, that show performance is strictly the Mind Games song, with no orchestration-- but when they wrote Do You Realize, they actually made the studio cut liek the Mind Games production, with bug sweeeping orchestral parts.
not sure if it was unconscious -- just the result of playing it so many times
hard to say.