Any danger would come from novices doing it in the middle of a bunch racing or training and causing a stack because they lost control when something required a positive movement and they either slip or react too slowly.
The pros seem to only use it when out on a break or in situations where they can get away without using a safe grip on the bars.
Any danger would come from novices doing it in the middle of a bunch racing or training and causing a stack because they lost control when something required a positive movement and they either slip or react too slowly.
The pros seem to only use it when out on a break or in situations where they can get away without using a safe grip on the bars.