I don't know if there are hidden reasons behind this decision,but the liquidity problem is a real problem for a broker if he wants to take care of emergency situations.
In 1929 and 1987 crashes, all of a sudden there was noone to sell to. "Sell,sell,sell!!!" "To whom?" was the talk between clients and brokers.
So you don't have to consider how the liquidity is now, but how it will become if and when there is a crash which after all is the moment for which all the security measures are in place.
With no liquidity, price is out of control.
And since noone can predict when it happens,security measures must always be in place.
In 1929 and 1987 crashes, all of a sudden there was noone to sell to. "Sell,sell,sell!!!" "To whom?" was the talk between clients and brokers.
So you don't have to consider how the liquidity is now, but how it will become if and when there is a crash which after all is the moment for which all the security measures are in place.
With no liquidity, price is out of control.
And since noone can predict when it happens,security measures must always be in place.
