Battlestar Galactica: on a recent episode, Captain Adama was shot, and was starting to code blue. Not having a defibulator handy, the medic opted to crack open his chest and massage his heart to restart it. Immediately after the procedure they show him lying on the table, with very few monitors around, with a simple tube in his nose. The scar from the surgery was too high up, it started at the base of his neck, and it looked like a simple red mound, not sewn-together flesh, as it should have looked. It should also have a lump at the top of the scar where a hematoma forms, and there should be other scars where drainage tubes would be inserted, etc.
I know the show is set thousands of years in the past, when their technology was far more advanced than ours (according to the show’s mythology) but not a very convincing portrayal of the surgery, nonetheless. I’m betting that, contrary to what it would be like in real life, he recovers soon and is up and about giving commands and being active.
Wonderfalls: In one of the episodes, a security guard from the gift shop has a heart attack during a robbery. In the cut outtakes of the show, the guard returns later after bypass surgery to show off his (very unrealistic) scar.
Heck, costume & makeup guys, you can find video on the internet that not only lets you see a surgery in progress, it shows what the scars looks like immediately afterward and at various points during the recovery process. There’s no reason you should not get the scars right on a TV show.