Maybe they feel Singapore "tarek harga".
They know Singapore desperately needs sand, and also wants to use
Johore airspace to save on aviation fuel, the cost of which is
always rising.
Now they wait.
For Singapore to offer Malaysia something for the sand and Johore
airspace.
Then it will be Malaysia's turn to "tarek harga".
Malaysia: Ha Ha Ha you want sand and use Johore air space?
Singapore:We will transfer all Malaysians' CPF in Singapore to
you.
Malaysia:But those are our people whose money you are holding, its
only right that you should do that, there is ar.. erm... no balance
of benefit...
Gotta be careful with those Malaysians.