A clear forward (backward for Axel type jump) take-off will be considered as a downgraded jump. This isn’t my opinion, these words are written in the Technical Panel Handbook. The take-off of the Axel must be do going forward, if not the jump must be downgraded. So, look at two different Axel jumps in two different National Championship.

On the left in the first of the screenshots series there’s a counter, then the momentum, and, in the fourth, the take-off. In the fifth the skater is already in the air, and he is going forward (look at his hips). The last screenshot is the landing.
On the right in the first screenshot there’s the exit of a spread-eagle, then the momentum, and, in the fourth, the take-off. The skater is already fully going backside. This jump must be downgraded and considered a double Axel, BV 3.30 points. And for the GOE’s…

Even assuming that there are all the other bullets, the 2, good take-off, is lacking. The jump can at best start from +3 before applying the deductions. Poor take-off? There it is. I’m kind, -1. Lacking of rotation? No, I’m not too strict, if a jump is marked with << for lacking of rotation in the landing, it receive the BV of the jump with one lap less and the negative marks. There isn’t a sign on the protocol (only because ISU hasn’t established a sign for the lacking of the rotation on the take-off). So I go with the smallest deduction, -1. This jump deserves at best +1, with the BV of a double Axel it means 3.63 points.

It’s not a big mistake, only 7.25 points gently gifted from the panel of judges in a single element.

Edit: Someone among my contacts has shared this tweet with a good slow motion of a jump that isn’t an Axel.

In case the tweet will be deleted, I’ve made some screenshot:

Really, good Backxel. Oh, a jump with this name don’t exist… A shame. So we must count it as a double Axel.

A clarification, because I’ve seen on Twitter someone a little perplexed. The first jump is from the competition, the second from a practice. The screenshot from the practice are useful because we can see that in the competition he didn’t make a mistake, this is his technique for the Axel, but obviously the marks must be given only for what the skaters do in the competition.

Now let’s watch the combo. The second jump, the toe loop, according to ISU, is the most commonly cheated on take-off. I watch the same two skaters.

For both skaters the first two screenshots are the take off of the first jump. Unfortunately for the skater on the right it’s impossible to see the foot, the camera is too close.
The third screenshot is the landing of the first jump, the fourth is the take-off of the second jump.
In the fifth screenshot the skater on the left is only a little turned forward, with his weight on the right foot and with the right shoulder much lower that the left shoulder. He is rotating, he isn’t yet fully rotated. Only in the last screenshot, when he is already in the air, he is fully turned forward.
In the fifth screenshot the skater on the right, fully on the ice, is almost completely forward. Even if I could not do a screenshot of when he is fully turned, it’s evident that, from this position, with his weight fully on the ice, he can’t jump without rotating a little more. In the last screenshot he is in the air, over 180° after the take-off. This is a double toe loop, not a triple. BV, in the second half, 1.43. In combination with a 4F, BV 12.10, the BV of the combination is 13.53, with a GOE of 1.10 (+1) the skater deserves 14.63 points.

Other 6.27 points of difference, with the previous 7.25 is a total of 13.52 points. Instead of 113.92 points the skaters deserves 100.40 points, and this even not considering the stiffness in landings (effortless, what it means?) and the components.
Oh, I’m so silly. I’ve forgotten that the technical panel must watch the prerotation only in regular speed. They have the slow motion, they can use it for the edges of flip and Lutz, but they can’t use it for the prerotation. Why?