I don't have a custom manufactured privacy awning, but I did buy a length of shade cloth to hang from my awning for the afternoon sun.
I think I put it up once, maybe twice. It blew too much in the breeze and it made me feel closed in. I don't mean claustrophobic, just it seemed like I was in another room and not outside under the awning.
Also, unless your RV is placed precisely you won't get that much benefit from the added piece. Which is a bit more annoying based on the simple fact that you purchased it to prevent that.