Thanks for your comments Izzie. I can quite believe what you advise for many parts of the UK, but the Isles of Scilly are remarkably free of such crime. They are
currently advertising for a new Police Constable for the islands. The guardian newspaper (in the link article) says: "any potential candidate would need to know how to handle a stray seal in the high street or be able to pacify drunken chefs in a row over salt."
Having said that, there is always the possibility of a Lesser Weever fish which is sometimes found buried just below the surface at low tide level. This has poisonous spines that do cause a painful sting to a small number of paddlers each year in the UK. This wedding party is well above that level.
John