When running minecraft with subtitles turned on it will always pop the subtitle 'minecart rolls' when ever a minecart entity is loaded. This can give players an 'xray' sense for when any underground structure that would contain minecarts is nearby which would be a significant issue for survival servers giving players that know about this an advantage over others in finding loot/spawners etc If a minecart is placed anywhere in a chunk and its then unloaded it will play the 'minecart rolls' the instant that chunk is loaded again when a player goes near it. Even if the player is a significant distance away from the minecart they will still get the subtitle.