The key word here is walking on the "beach". Oceans are very healthy environments for micro-organisms, including bacteria. Here on Maui, the hospitals are very aware of the amount of staph that lives in the sand along the islands beaches. Anytime someone gets a minor cut and spends time in and around the ocean here, the odds are very high that they are in for a serious infection, one that would pose extremely high risk to any artificial joints. Before I had my resurfacing, this risk of infection from minor cuts being exposed to the ocean environment was probably my biggest long range concern, and it continues to be.
I am in the ocean for many hours every day, and any minor cut, like I am dealing with right now, is treated with thorough cleaning, antibiotic ointment, and layers of waterproof bandages like my life depended on it; I know that my hip does.