I am an occasional cycler at best, have had the rack for about a year and have removed only twice. Locking knob felt a bit cheap from the get go, but manageable. Removed the rack today to change my tires, upon attempting to remount the locking knob began malfunctioning. Plastic piece for grip spins freely around the bolt, rendering me unable to remount my rack 20 miles from home and forcing me to call my wife out to pick up the bike.
Check website that afternoon to see they are out of this part, likely due to high demand for replacements.