I find it very hard to believe that two South Korea based Chaebol memory producers would have no wind of this from the other.. more likely is that they both agree that it is not in their or the nation's interest to take on too much of a risk profile... while also balancing the risk of appearing to be colluding.
It's more advantageous long term for them to be oblivious to it. Ultimately gives them what they want which is reduced supply and increased pricing for them.
