Clone a VM with THIN disk type as FLAT

I'm trying to clone a VM from a template. For that, I have a code as below 
 

VirtualMachineRelocateSpec rSpec = new VirtualMachineRelocateSpec();
...
rSpec.setTransform(VirtualMachineRelocateTransformation.FLAT);

As per this link

for thin provisioning , use sparse
for thick provisioning , use flat

Now, I want to check a condition where the underlying datastore doesn't support thick provisioning but I'm still passing transformation as flat (according to VMWare documentation here, which is a requirement)

In my case, the VM gets created with Thin provisioning. I want to know whether this is expected behavior or not. Should VMWare API throw an exception saying thick provision is not supported on this datastore.

Can anyone verify this?