You should be able to teleport a player into an identical room without them noticing, but whenever they teleport, their arm moves/resets, and it's easy to see that you teleported. For maps that mess with the player by teleporting them around, it's not nearly as confusing if you realize you are teleporting.
MC-52815
Arm Moves When Teleporting
Resolved
Incomplete
0
Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases. If this has been done, we can reopen the issue.
Keep in mind that the "Resolved"-Status on this ticket just means "Answered", and that we are waiting for further information on whether this issue still exists or not. We will reopen it as soon as the requested information has been delivered.