I think the Trust is required, so that you can Entitle the Pool. If the users reside in another Domain, than the one the Connection Server is in, then it will not be able to find the account you want to Entitle.
We have a one way trust between the View Connection Server (CS) Domain and the Entitled Domain, where the CS Domain trusts the Entitled Domain. In our environment the View Desktops are registered in another Domain, they have 2 nics one to the Entitled Domain network and another to the Desktop Domain. So in total we have 3 Domains.
Once we have created the one way Trust, we create a Global Group in the Entitled Domain, add users into that group. Then we create a Domain Local Group in the CS Domain and add the Global Group from the Entitled Domain into the Domain Local Group. When you Entitle the pool, you will see the Domain Local Group, which has the Trust established to allow user accounts in the Entitled Domain Global Group. When the users log in, they log into the Entitled Domain and are presented with a pool of desktops in the desktop Domain. We add routes into the View desktop, so it finds it's way around. We also hide the Domain using the VDMADMIN tool in View. So the users have to enter their username as username@EntitledDomain.
It's confusing, but works!
