The SilentClutch hubs are silent. You wouldn't necessarily want to use them because they only used the system on low end product, but if you do then you can certainly sneak up on people.
It's for my ultra bike and sneaking past dogs. I liked my old Shimano Ultegra hubs for crits.
You could freewheel away sitting on someone's wheel without them knowing.
The SilentClutch hubs are silent. You wouldn't necessarily want to use them because they only used the system on low end product, but if you do then you can certainly sneak up on people.