Proponents of RCD protection tend to gloss over the fact they won't protect you if no current flows to earth. You can put yourself between live and neutral all day long standing on a wooden floor and the RCD is just going to think you're another balanced load and do nothing about it. The hairdryer falling in the bath is always used as a demo...but I wonder...what if the bath is a modern plastic one with a PVC drain? How will the requisite current flow to earth and trip it? I think it does need to be publicised that the RCD will not prevent all electrocutions.
As for leaky appliances, I've been lazy and not got around to replacing the leaky RFI bypass caps on my General Radio beat frequency oscillator...I just plug it into an isolating transformer so it doesn't trip my workshop supply.
Instead of the 'whole house protected by RCD' approach, I prefer to protect individual circuits or appliances. The HPM Electresafe (and their Clipsal equivalent) GPO's are great for that.
