Could be nice to have an official ruling about this.
Here was how i asked this on BBG :
Here is the point.
If a scout or an army makes a blocus on, for exemple, a Great General, can the blocked player use his Great General card ?
He don't lose his card (like when the GP is killed) but cannot use it as a blocus is occuring ?
In the case where the player owns 2 Great Generals and 2 Great General cards, and one of them is blockaded. Do you randomly decide which card can't be used and/or lose his permanent bonus ? Or does the blockaded player decide which card he can't use ? What happen if one card is a permanent bonus and the other one is a "discard to use" card ?
Or simply block a GP don't affect GP card ?
No one could give clear answer about it.
I agree that it you follow the text litteraly, it seems blocus don't affect GP card (and this, probably to avoid some tricky issues).
But the question came to the mind of lot of player, considering that a blocus on a GP block the card too. And they play it like that (the blockaded player decide which card he can't use due to a blocus).