I'm not sure what you are referring to. There is no way that I know of where you can get instant diamond trialling.

It is not possible to simply ask for a diamond trial and be diamond straight away. There was recently a diamond trial promotion if you were platinum. There was also recently status matching from other programs to become HGP diamond.

Now, the diamond status is not given until you stay X times in a trial period. The problems before have been rectified, for better or worse.