I'm sorry, but that just doesn't explain anything.

Firstly, you're accusing Mt Gox to be doing stuff that they were not doing. The still ongoing investigation shows something quite different.
http://www.zdnet.com/article/police-suspect-mt-gox-bitcoin-theft-was-an-inside-job/
--> Bitcoin theft, not bitcoin scam.

Secondly, you suggest that there would be such a fake exchange today, which I bet you cannot prove.
What you describe is actually extremely hard to pull off.
People come and go, unlike what you say. In the example you give, it would required only 1 out of 33 bitcoins to be withdrawn from that exchange for it to start running on fractional reserves.
Such an exchange couldn't run a month before being discovered.

Thridly, to get this done the way you say, the volatility needs to be low. In periods like today, the volatility within an exchange can be higher that 30% a day. That would kill your idea of a scam in a minute. (Today, I saw the price on Bitstamp go from $159 to $195 in less than 10 minutes).
The 3 little percents you were mentioning would be swept out of the way real fast. And making more of a difference would draw attention.

Fourthly, 3% isn't enough for manipulating the prices on a market with such a volatility. And wouldn't explain what is happening now.


So... Still waiting for something more believable, sorry.