Well, I certainly concede that a 30mA GFI outlet at 240V to ground could still pose quite an electrocution risk. I picked on 30mA because that's the lowest GFI breaker that's easily obtainable in a wide range here; in fact many houses in rural areas now have a whole-house GFI of 30mA.
But 10mA types up to at least 20A are available, and would undoubtedly be a better choice. And whatever GFI is used, it would at least be better than extension cord hair-dryers run from a non-GFI outlet.
I never came across one of the new blow-dryers while I was out there (it's nearly 6 yrs. since I came back). How exactly do the "immersion detectors" work?
If you applied the 50% rule PER APPLIANCE, then our washers and dryers would still pass, as the ring is a 30A circuit, giving 7200W maximum. But with two 3kW appliances running simultaneously that only leaves 1200W, and in too many homes that 30A ring is also feeding all the kitchen sockets where kettles, toasters, etc. are likely to be in use. And in remodeled kitchens, I have seen washer, dryer, and dishwasher all on the same ring.
You'll see that in the IEE Regs. a ring can feed up to 100 sq. meters (originally 1000 sq. ft.) of floor area. In many older houses there's only one 30A ring for all sockets (except the one sometimes fitted to the cooker panel).
Even where two rings are provided, as is common now, in a 2-story house they are often wired one for each floor, which to my mind is not the way to get a reasonable distribution of load.
Some guides recognize the problem, but then go on to suggest that with the increased load in a modern home it may be a good idea to install a separate ring for the kitchen-area outlets. That seems to me to be missing the point that it's the kitchen area which is carrying the bulk of the load and needs to be divided onto separate circuits.
I hadn't thought about increased EM fields from a broken ring conductor, but I think the possibility of overheated wiring should be of greater concern.
There was a lot of fuss about HV lines a few years ago, but the protests seem to be directed toward cell-phone towers these days (sometimes by people who spend all day on their own cell-phone and who have obviously never heard of the inverse-square law!).
The prevalance of brick and masonry walls does make cabling awkward at times. Where a timber floor is used (e.g. many pre-WWII homes) the ring cables are generally run in the crawl space and brought up to each socket behind the skirting-board (baseboard) and set into the wall. (In earlier times it was actually very common to just screw surface boxes to the board and take the cables straight down trough the floorboards.)
Where the floor is solid concrete, the ring has to be run in the attic and cables dropped down the walls to each outlet, or channeled horizontally along the wall. With two cables to each outlet, it's a lot of work anyway, so I'm not sure that changing to radial circuits would make it any harder in that respect.
