Outstanding point.
The richest LCP in my NS unit is a purchaser for Korean govt in third world countries, if you don't have plenty of ang kongs, you don't have the balls to do this job. He has very high income, not necessary to declare. One day he told RUN he bo bian, went to buy a kopitiam to generate some income so that he can buy a BMW and house with some loan. Imagine if he had paid in full cash for a >$3m property, he is asking for trouble.
So for this type of people, they wanna take bank loan but their declared income is too low to TDSR requirements. This is why we will see huge sell down in the >$3m properties this year. In the current low interest environment, only foreigners who wanna launder their money will pay full-cash for a multi-million property.