If a motorcyclist is resting his feet on highway pegs, his feet are not on his foot controls. Some argue that this is unsafe because the driver will have less control over his vehicle should an emergency present itself.
While it is true that the driver cannot access his controls while using foot boards, using these devices during long journeys allows the driver to plant his feet firmly on a flat surface. It also allows him to stretch his legs a bit, given the forward position of the boards. This can reduce risks associated with leg stiffness and cramping.
Boards should be used instead of pegs in a variety of circumstances. These include long journeys, when tingling is felt in the legs, when a driver is tired or bored and needs to shift his position to remain focused and when cramping is felt in the legs. However, when none of these circumstances present themselves, it is safer to use pegs.