In Indonesia as well as in Malaysia I myself have carried out "experiments" when I board a plane.
I put plastic bottles (some time one, some time more than one) and filled them up with liquids, and then put them into my luggage and also carry on luggage.
They let me pass. No problem.
And as I have mentioned in another comment - I have seen with my own eyes that the airport security officers let people (supposedly female) who cover up their face to pass the security checkpoint (without having to reveal their true face) and board the planes (all the while with their face covered).
That is why I say, in Malaysia and in several other Asian countries, it will be very easy for any terrorist to board the plane.