NoRotate

When the server teleports a player — by command, by a plugin or as an anticheat setback — it sends not only a position but also a head rotation. The vanilla client accepts it and looks where it's told. NoRotate throws the rotation away and keeps the camera where it was.

Cheaters want this so KillAura and Scaffold keep their target after a setback, and so plugins and minigames that turn the player — toward an arena, an NPC, a starting point — have no effect on them. The dangerous combination: the player gets set back for a violation and carries on fighting with the same aim, as if nothing happened.

• After /tp or a plugin teleport the player keeps looking where they looked before
• At the start of a minigame everyone faces the arena except one player
• After an anticheat setback the aim stays locked on the opponent

The vanilla client answers a teleport strictly: it confirms the teleport by its ID and immediately sends back a position and rotation — exactly the ones the server set. NoRotate confirms the position but sends its own rotation. The answer is tied to the teleport ID, so ping doesn't interfere: however long the packet takes, the rotation in it has to match.

There are honest edge cases: the server can set the rotation relative to the current one while the client's view has already moved. The check has to account for that, and a single mismatch is evidence, not a ban.