In the early trips we never locked the dinghy but things change and you need to use common sense. BVIYC always provides a long cable and lock for the dinghy. We use our judgement as to locking ashore. If we are close by in daylight hours usually not, but if we go to dinner somewhere at night where we do not have eyes on the dock ( Cane Garden etc.) we will lock the dinghy. We always lock it at night to the boat. Just don't want the hassle of losing it.