an example, there was an experimet done a few years back.. cant find a link.. about day traders having better trading abilities before they were told they are actually dealing in real money transactions.
Yes! i do understand that , people predict and the rumour alone cause a rucus and a rise , if they actually do it , the value stays and it again falls.
This has actually happened before --- 2012 on Intrade Mitt Romney's campaign bought millions in Romney shares to seemingly boost Romney's chances. What ended up happening was the market quickly corrected to the prior odds showing Obama with a higher chance of winning. Using real money usually forces people to do what they'd actually do (and in this context I definitely consider Bitcoin real money), and when it doesn't (e.g. Romney campaign) the market corrects.