AFAIK there are no requirements for regulators, the majority aren't Pi tested and some still run single burst discs. If we start jumping up and down on this subject where will it end? Pi marked macro line, elbows, in-line regs, LPRs, solenoids, rams/bolts? How much will that push the manufactures costs up having the components tested and approved?
I'm not condoning unsafe products and practices but I'm certainly not condoning nanny state 'elf & safety regulations! How often do you hear of a regulator failing?