This aricle suffers from the same flaw that it professes that other articles have --- the assumptions that circumstances that everone faces is the same.
Having been an shop floor guy who has appeared for CAT and done an MBA and now in finance ,i can say that it is sometimes good to keep this a secret.
There is no guilt .All the same if you are in a job where returns from you is long term - say in product development , your boss is likely to give you less importqance if he knows u are writing CAT.
The decision to say or not to say should be upto the individual and he has to consider the nature of his workplace , his boss's nature etc.
