Proof the Chinese cheated? When I watched the gymnastics, I truly doubt they were all 16 (or almost 16 -- one won't turn 16 until December if I remember correctly, but that's still legal). But I have to depend on the IOC. My impressions really don't matter.
Puddle Jumper, there have always been political implications in almost any sports competition -- and not just the Olympics. Even back in Little League baseball, didn't you always suspect the umpires were slanted toward your opponent?
And consider the pattern of violence at international soccer competition?
Any time judging is involved, whether scoring, calling safe/out, etc there is always a subjective element. Actually, I have to admire the IOC for their efforts and dedication. They won't be perfect, but they are trying. (and some scoffers would say very trying

)
I am very glad they are investigating more. That definitely lends credence to the process and standards.