I've done it on a couple ladder type climbing sticks. It seemed to help but it doesn't make them silent. You'll have a lot of trimming and stuff as it swells and makes it necessary so you can stick them into each other. I never tried it on a climber or anything like that.
I've heard of people putting carpet up on the tree that they are sitting in to quiet things down. That way their jacket doesn't make a brushing or velcro trype noise.