The question is more of a philosophical one, as you gotta define what you mean by hedging in the first place.
As many of expressed, there is no such thing as a fully hedged risk-free portfolio.
Every portfolio is hedged only with respect to specific components of risk, but exposed to other components of risk. Convergence or statistical arb has the risk of divergence and vice versa... options portfolio have a multitude of non-linear parameter risks ad yada yada.. People willingly or unknowingly take on a position to gain exposure to specifically those unhedged components in the first place, to make that extra return.
As many of expressed, there is no such thing as a fully hedged risk-free portfolio.
Every portfolio is hedged only with respect to specific components of risk, but exposed to other components of risk. Convergence or statistical arb has the risk of divergence and vice versa... options portfolio have a multitude of non-linear parameter risks ad yada yada.. People willingly or unknowingly take on a position to gain exposure to specifically those unhedged components in the first place, to make that extra return.

