I've never seen a split rim, except on aircraft wheels where this is a common practice, and they usually get only 15 - 20 PSI.
But they are still dangerous to life and limb
Even when I was in the Army Combat Engineers, in 19mumblegrumble, we were using the Split rings on all our truck / heavy equipment tires.
When reinflating a truck tire in the field(off vehicle) I'd always place the tire with the ring side down. Luckily I never has a problem.