There is a delay on cable and satellite TV. While visiting a relative, I had my nephew and niece convinced I was psychic. Watching a football game on my phone, I was two plays ahead of the cable broadcast of the same game. I was 'predicting' what would happen, type of play, the players, penalties, etc.
Padding recording times is a semi-solution at best. I can only record 2 shows at once. During prime time, I record two shows during the entire period. Frequently my recordings are on different networks, so padding the time overlaps another recording creating a conflict. Missing the last 30 to 60 seconds of a show is kind of irritating. I am not sure if there is a 100% solution. Sports are broadcast via satellite to local stations to transmit OTA. There are fewer hops involved, so OTA should lead cable and satellite providers by 3 to 40 seconds. For cable, if you live physically closer to the node, you will get your picture/audio a few milliseconds before someone further down the line. Cable transmits at the speed of light, but time lags occur because of distance, physical connections, the number of hops the signal makes between you and the provider infrastructure, and some other factors. At one time, I had a very long cable run to a part of my house. The TV in that room was just slightly behind the TV in the room closest to where the cable enters the house. It was like hearing an echo. If you want proof that this happens, call a relative in a different market area who has cable during a sports broadcast. There will be a noticeable difference. My mom is 200 miles away and sometimes she gets the signal before I do, and other times hers is behind mine. Once, during a football game where I started almost a play ahead of her, the two finally synced and then I was trailing her by over one play. Since there is nothing that can be done about that, you have to find the fun in it. I enjoyed being a psychic for a few minutes.
I remember with OTA with its analog and digital before FCC forced the switchover. Analog was faster than digital. It was amusing. I assume OTA is faster than cable and satellite (never tested).
Don't forget those "leap seconds" that get inserted because the earth's rotation is slowing down (due to atmospheric friction, not global warming, BTW). Not every GPS receiver's time code is correctly set to include the "leap second" offsets between UTC, TAI, and GPS. Most cable operators don't know the difference, nor do they understand the impact it has on their video program distribution. The goal for both TV networks and cable companies is to compress the video programming enough that they can insert (and bill for) one or more added commercials per program slot.
Here's what the U.S. Naval Observatory at tycho.usno.navy.mil/leapsec.html had to say a year or so ago -
"GPS Time is NOT adjusted for leap seconds. As of June 30 2015, and until the leap second of December 31 2016 TAI is ahead of UTC by 36 seconds. TAI is ahead of GPS by 19 seconds. GPS is ahead of UTC by 17 seconds."
** TAI is the acronym in French for International Atomic Time which is calculated by using a bank of atomic clocks which are not affected by the earth's rotational speed. It's a third time reference not often used for synchronizing worldwide data networks.