There is.
Q:How does the player protection work.
A:
You can't attack (a)anyone who has 5x your points or (b)anyone with /5 your points. They can't attack you either
Ex: If you have 6k points, you can't attack anyone with more than 30k points and anyone with less than 1.2k points..
Important: The player protection only applies if you have less than 10k points.
Which means when you reach 10k points, (a) is disabled. Even someone with 300k points can now attack you.
(b) still applies. You sill cannot attack someone with who has less than /5 your points. Until they reach 10k.
There is also a FAQ in-game and in the forums.
