Burst disc for HP tanks

[DRE]

It's a small Stainless Steel disk, which replaces the copper burst disk. It's much tougher so you won't have to worry about it blowing. I've heard of a couple of recent incidents of burstdisks blowing during a dive, so it can and does happen. Why have this failure point?

Also, I know of people using plugs instead of burstdisk assemblies. They're just bolts that screw into the burstdisk threaded part of the valve. Although this is the best way to go in terms of safety, diveshops can tell they're not a burstdisk assembly and might refuse to fill your tank.

BTW, all valves and manifolds sold in Europe do not have a burstdisk, yet they've never had any problems with tanks exploding because of this. I wonder why?