Apparently star balking is also used when negotiating a new contract.
In the current implementation a player starts balking when you have too many good players, however we should go as far as saying that a defender should only balk if there are too much good defenders, midfielders when there is too many good midfielders, ... keepers... , ... attackers ...
On the other hand players don't want to play in a league for which they are too skilled, so that's a type of balking that needs to be implemented.