That is absolutely untrue . You do not have to replace the deck. First off , its pitch not sap and it will eventually dry up and stop running. Until it does you will have perform light maintenance consisting of cleaning up the pitch when it runs maybe 2 or 3 times a summer in the spots where it is heavier. Not the end of the world folks. I have had direct experience with this using pine that had not been kiln dried to a high enough temperature before using the wood.There is nothing you can do.. it won't stop. The boards need to be replaced. I've noticed deep penetrating oils make the problem worse.