one problem we had last year was that it'd bring water up when people exit causing the person infront of you be rather p***ed off. though it varies with some paddles...we only experienced it with a few people, but once removed no splashing.
i have never heard of that problem with taped up blades causing water to be tossed, unless you taped it up pretty bad with edges and overlaps hanging everywhere. my guess is kicking up water is probably attributed to doing something wrong in the water (technique wise).
i tape up my CF paddle and OC blade. it really protects it from accidental beats on the gunnel, paddles clashing or as paddle boy said... rocks during low tide (stupid north side cambie bridge).
i had a conversation with an OC paddler from another club and he brought up a point that taped up blades often trap water on the edges or under the seams which could rot the wood. personally i don't believe that bull cause i rince my paddle off with fresh water every time i finish paddling.
