True, and the decoders in receivers already have this capability, since they keep decoding even if the forward-error-correction can't save the stream any more, resulting in similar artifacts. I'm not sure why it's not done on a channel change, perhaps it's the manufacturers not wanting their TVs to routinely show glitched footage, or perhaps advertisers don't want it because it would be against Corporate Design rules to glitch-effect the logos they use on the daily.