In this article from the Financial Times, whether or not completely passive approaches should be used when investing in currency, is discussed by managers "who liken the strategy to "picking up pennies in front of a stream roller".

Diane Miller, principal at Mercer "says the pattern of returns for managers who use carry as a significant component of their process is that prolonged periods of good returns can be followed by large losses. "A pure carry strategy can be likened to picking up pennies in front of a steamroller - it can be profitable but you might get flattened."