Does the device respond to all commercials? If not approximately how many will it pass?
Since the shortest commercial block is 2 minutes (rare exceptions are shorter) CK learns the commercials during this time. CK will respond to the commercials that it has learned next time around. Without learning any commercials, CK is about 75% effective. As CK learns the commercials, the % goes up.
Does the device fail to respond to commercials, if so how will that happen?
Without having learned any commercials, after 2 minutes, the commercials will come back on. As CK learns the commercials,you'll hear less and less of them.
Will it mute during a program, with no commercial present?
Programs such as Law and Order with black screens between scenes caused a false trigger. I added a 5 second delay and a skip trick which took care of the problem. There may be other programs that CK will trigger on but rare.