The only reason they die from this is that they can't keep up with mom and starve
I wouldn't be as bold as to say the only reason, but I agree that if the splints means they can get up on their own and stand to suckle I am all for splints.
The important part is to make sure they can't chave the leg. I use 2" poly pipe cut lengthways with both ends heated up and flared open. I then put thick cotton wool on the entire leg and keep it in place with elastoplast, then I put the pipe splint on and duct tape it like sir loin has done in his post above. As soon as the calf moves well take one splint off, wait a day or so and take the second one off.