I own two canon cable releases. One I bought in 2003, the other my father gave me before he died. I've never had a problem with either.
I've got the extension cables too. No problems there either. Expensive, but equipment you can pretty much forget because it works.
I've used mine a lot in windy, dusty, sandy environments in the southeast. Still no problem. Walked on them, accidentally dragged them over the ground. Not a glitch in sight.