Elements that are in-game are treated as if existing in the fiction and can be acted upon by characters.
Players are in-game or "in character" when they are acting as their characters and not themselves.
Most larps will strive towards having a clear definition of what elements are in which state, but it is often up to the individual player to make judgement calls during play. [[360º]] games aim towards having as many elements as possible be in-game.