As the others have said you do not need a DECA unit to run RVU assuming your home network is configured properly (which is why they don't support the direct Ethernet connection, they don't want to troubleshoot your network).
I just went through this and it was frustrating to me that they needed to send a tech out but I can sort of understand why they do. We are probably not your average customers running network cable throughout the whole house connecting everything that way and they are not built to support us, yet.
The tech I had was very nice and he was puzzled by all of this himself but in the end installed the DECA to make DirecTV happy and to cover his own backside. I removed it once he left and all is well. The picture is superb and the menu / channel changing works very well. The TV is a Samsung UN32F5500 I ordered from Amazon.