The jetties are wooden walkways, kept afloat by buoys, the boats they're lashed to, and their relative lack of density. The central jetties surround the cruise ship and are wider, denser, and better maintained; while it's very possible to fall or be thrown off, almost every piece of walkway here has safety railings, some even reinforced with metal. Life preservers are placed at intervals throughout, and access to many ships is available through ladders and walkways. While it might seem that cover would be sparse, the twists and turns and hiding places between ships actually offer many opportunities to get lost or hide here.