Read and you will see how difficult it is to stop someone from spying.
Also, keep in mind castles have more counters per building.
43 spy buildings at level 7 = 2150 spies
When spies vs counters are equal:
Gives enemies a 5% chance of lvl 3 access, and 0% chance of lvl 4
= 36 lvl 5 counter buildings needed
= 26 lvl 6 counter buildings
= 21 lvl 7 counter buildings
When spies are half as much:
Gives enemies 5% chance of lvl 2 access, 0% lvl 3, and 0% lvl 4
= 72 lvl 5 counter buildings needed
= 53 lvl 6 counter buildings
= 43 lvl 7 counter buildings
* Max amount of cells in a castle is 49. 11 of those cells SHOULD be used for other things. That means you have 38 spaces for counter and mirror buildings. No room for houses, warehouses, or military buildings. In other words, it's a lost cause trying to stop someone from gaining access. Oh, and don't forget lots of players now have perfected spy buildings

The end lol