You can prevent mold in the tape by coating the sail.
With some sails, the tape used darkens over time. This is due to mold. Through the stitching holes, dirty water with spores of mold, algae, etc can get between the layers of sailcloth. Over time the tape will become moldy and if you are unlucky you will also get mold between the laminate.
You can prevent this yourself by coating a sail. By sealing the stitching holes that way.