The really odd thing about this screen is it comes up AFTER the signal is restored!!!!! Try pulling the coax to the dish while tuned to a LIL. You'll get the normal lost signal screen. Now plug the coax back in. Chances are you'll get the "don't call us" screen when the receiver detects signal again. Very annoying and obviously a bug. I submitted a report months ago but they haven't fixed it yet I guess.
Agreed that this slate should disappear and show the signal when restored. I think Dish figures that we will tune to something else, then tune in later to the problem channel and if the signal has been restored, we get the picture.
The other problem, and I think you eluded to this, is that this slate will appear for any number of reasons that cause a hiccup in the system that has NOTHING to do with signal strength or LNBF's or anything else that relates to a signal issue. Then you have to know to tune to another channel, then tune to the slate channel again, and all is well. But not many people know that.