When world borders are closing in, if you stand still you the border will go right through you. Leaving you on the outside. You are no longer able to move whatsoever not even towards the border, You can't even fall down.
Linked issues
is duplicated by 4
Comments 3
http://www.reddit.com/r/Minecraft/comments/23v9ep/minecraft_snapshot_14w17a/ch0yfwv
Dinnerbone
If you're outside it you get stuck but that's temporary behaviour, I want it so that you can get back inside if you accidentally find yourself outside (such as the border shrinking on you)
Twitter:
Nathan Adams @Dinnerbone
Okay we gave up trying to get moving-back-into-the-border logic working so pushing a snapshot now, you'll just get stuck if you're outside.