Using a short piece of fuel tubing to keep a clevice closed assumes you have never seen a piece of fuel tubing split. Or that it will not split while your plane is in the air and allow your clevice to open. Wake up! Fuel fuel tubing splits all of the time. On a clevice it is under much greater strain. I keep seeing people replace the short piece of tubing when it splits with another short piece of tubing. Where is the common sense? There are much better ways to prevent the clevice from opening.