[David R Leifheit]

I've seen many of these changed, in the yard and along side the road. Forklifts and other equipment tend to have these kind of rims, bigger trucks as well.
The company I worked for had a contract with the tire service, they would come out to the yard, take the tire off the vehicle, deflate it, use a BIG hammer to break the bead, use two bars (which I have found can still be bought) to open the locking ring and remove it. Then reverse the procedure to put it back together. Yes, they had a locking air chuck (most of the time) but never a cage or any other "safety" device. Never had a problem with any of them.
The only problem we ever had with a "split rim" was one of the forklifts had 2 half rings for the lock ring. When the tire went flat, if you had to move the forklift the locks would fall out and the tire would end up coming off.
Used to hear the old timers talk about splits... they seemed divided on the subject. Some would say the cage and safety stuff made it harder to do, as long as the parts were clean and seated right there wasn't a problem. Others always had some horror story about someone they knew who saw someone get injured (never seemed to be first hand though).
I'd have to check, but the last time I knew the "Les Schwab Tire Centers" would still do split rims. They do big trucks (log trucks mostly) and heavy equipment so I expect they see a lot of the split/locking rims.