What happens when people try to pump and dump collateralized crypto curencies. Also cuz it is free float, wouldn't the price change anyway, will the price differnce be marginal, such as tether or will big pump and dumps devalue the currency below the collateral.

These are legitimate questions that the @bitshares community should take into considerations before bringing such a dangerous game into mainstream adoption. Please note, the crypto space is filled with unpredictable moments--look at what happens to SBD now!