I just created a beacon that can accelerate the movement of a player.
When I run through the area near the beacon, I often teleported back to the old position, and server prints "0xAA55 moved too quickly."

It's really annoying because even you create a new server without any mod, generate a new world, wait for 1 hour, join the game, and play, you will also find that if your network is not very good, you could never run because running will let the server teleport you back, and you will get a message "xxx moved too quickly."