Rules wise, the only issue with an RBR is any uncached data may not be committed to the drive before its reset, so you might lose a show or have a corrupt file system.
I tried pulling the plugs on both receivers, which should be better than an rbr.
Anywho, directv acknowledges this as a known issue. From what I hear, if a receiver is used as a client for mrv, after that it cannot be used as a server. Along with a bunch of other issues. Looks like they stuck some major new protocols in, and looks like we'll all be looking forward to Friday a bit more than usual...