Players with " (double quotes) in their names can't be kicked out of a world. This combined with MCPE-130250, you may make them unable to cope with griefing.

Steps to reproduce:

1. Add " to another player's name
2. Have the player join your world
3. Kick the player out from the Player Permissions menu

Expected Results:
The player got kicked out of your world

Observed Results:
The player is still in your world

Note:
As far as I know, you can only be added the double quotes in the name on Nintendo Switch.