They were both placed on probation.
..and that makes sense? Lets run through each incident.
1) First NW race of the year, Carl intentionally wrecks Kez and half the field. If anyone believes that Carl misjudged his front end by a foot, I don't know what to tell you.
Kez doesn't retaliate.
2) Atlanta, and Carl is running at the back of the pack with Kez. Carl gets a very bad restart, and Kez holds up while Carl tries to force his way in front of Logano. Carl is hovering between the middle and high lines when a car passes both drivers on the low line. Kez drops to the low line and gets a run on Carl, who quickly drops to the middle line. While the cars in front run 3 wide through the turn, Carl decides he wants to drop down in front of Kez. Problem is, he's doesn't have the speed and isn't clear. He runs Kez below the yellow and gives him the finger while hooking his bumper, eventually wrecking himself.
Carl responds to Kez not giving him what he wanted by trying to turn him into the outside wall at 190mph. When that failed, he intentionally turned him backwards entering a high speed turn. 3 weeks probation? Really?
3) At Gateway, Kez has a dominate car, and 171 laps into the race, Carl drives into Kez's rear bumper and tries to wreck him. Kez saves it. On the last restart, Carl is driving way down on Kez, and Kez eventually refuses to move. There's contact, but Kez backs off and gives Carl the position back. When Kez beats Carl into turn 3, Carl hangs high and sets Kez up and turns him into the wall with the field bearing down for the checker flag. Carl yells "That was AWESOME" after watching 11 cars pile up in a huge wreck.
Tell me, why was Kez put on probation? He's racing 'have at it' while Carl turns psycho again and again. By placing Kez on probation, NASCAR gutted their 'police yourselves' policy. Carl should have sat out 2 NW races for wrecking for blood again and again. Then he could sweat out the rest of the season waiting to see if Kez would retaliate.
IMO, Kez was running away with the championship, and NASCAR wanted Carl back in the hunt to keep things exciting. Also, NASCAR wanted Carl in the chase, and they were afraid Kez would retaliate in a cup race and ruin his chances.
Carl still had a rash over being out driven by a rookie at Talladega the year before, and actually blames Kez for the wreck Carl clearly caused. "Kez came up a little". You ran into his bumper in a 180mph turn. Of course you got him loose, you fool.