It's unwritten beach etiquette on Phillip Island that shoes, beach towels, surfboards etc. left above the high water mark are not taken -- that they remain safely in place until their owner returns.
In a similar manner, and on King Island where we lived in the 1980s, long strands of bull kelp pulled from the water and left to dry above high water mark belonged to the person who pulled them out. No one ever touched anyone else's kelp, and with each strand having a value of approximately $10, the temptation may have been there for some people. Bull kelp is one of the world's largest algae species and is remarkable for its strength; able to cling to rocks in surf that could crush a boat in minutes. Its honeycomb structure gives it buoyancy to stretch and float, and it is rich in alginates which are used to thicken foods such as ice cream and many other commercial products.
With dogs, people have them on leads when others are on the beach, and free when the beach is empty of people and dogs. Picking up dog droppings is another of those beach etiquette habits that makes the beach pleasant for everyone.
Saying, 'Hi' or 'G'day' to anyone approaching you along the beach is a friendly habit practised by most people on the island. People from 'away' seem reluctant to meet your eye, are inclined to walk by as if everyone else on the beach is invisible. This habit makes it abundantly clear that these people are from the city, and I always feel a stab of sadness at their lack of trust and friendship.