It's possible that the purple sign was accidentally put on sideways. Or it was put on correctly, and they want to encourage people to lie on their stomach and walk directly through the earth. It's a difficult hike, but definitely worth it.
In all fairness to 6, it is fairly curly as well. But 8 is definitely more curly, so this answer appears to be correct. It will be much harder to find the difference between the letter O and the number 0.
If you're going to fall, make you're in line. Falling in a random, non-line location is strictly prohibited. Usually when people fall it creates a lot of chaos, but this sign wants you to do it in a neat and orderly fashion.
Okay, this guy is probably breaking the rules just a little. Looks like there's some contact with his cheek and forehead. But once he figures out how to only touch with his eyes, he'll be in the clear.