I have used the egg, the water balloon, rubber hose, etc methods. It does work. With some horses, it works permanently, with my particular horse, it worked for that particular ride. With him, "tomorrow is another day"...
Rearing, in my opinion is the most dangerous thing a horse can do. These methods to me are not cruel, cruel is locking a horse in a stall for 3 days without feed or water. Cracking an egg over a rearing horses head is harsh, but maybe a neccessary evil in my opinion. People say they have horses that rear. And I do know there is such a thing as an occasional rearer, but when you have a horse that is a chronic rearer, you have a very dangerous animal. Ruling out pain, saddle fit, and fear leaves a stubborn ornery horse. I know, I have one. And I love him dearly. But rearing is dangerous. Just my opinion.
"Be a best friend, tell the truth, and overuse I love you
Go to work, do your best, don't outsmart your common sense
Never let your prayin knees get lazy
And love like crazy"