Only 3 active C31's, you can have up to 8 clients authorized. Any active client over 3 would get a message saying server busy at the moment (or something like that).
Actually any active client past 3 will get a screen telling them that it can't access the HR34 until you turn off another client I believe. The HR34 can only stream out to 3 RVU clients at any given time, whether it is a recording or live TV.
I too went to the website and was suprised it let me add 5 C31s to an order, as we were originally led to believe the DirecTV was only going to allow 3 RVU clients on an account at this point in time. I guess they have decided not to go through with that. They are however still charging $6/month for all 5 RVU clients which I think is a ripoff since you can only use 3 at a time (I feel you should only have to pay for 3 clients, no matter how many you have).
In my case for my parents order it looks like it is actually going to make the most sense for me to get one HR34, 3 C31s, and two standard receivers. This way they will get everything with no up-front costs (saving $98 over getting 5 C31s). This should work fine for them since they are in an MPEG4 market, so the standard receivers should automatically be upgraded to HD receivers for free. Looks like I'll be busy in a couple weekends rewiring their house to get it ready for DirecTV (I prefer to do it all myself first so it's up to my standards).
Sometimes when I reflect back on all the beer I drink I feel ashamed. Then I look into the glass and think about the workers in the brewery and all of their hopes and dreams. If I didn’t drink this beer, they might be out of work and their dreams would be shattered. Then I say to myself, "It is better that I drink this beer and let their dreams come true than be selfish and worry about my liver."
-by Jack Handy