BigB,
How often would a situation like you've pictured occur?
I'm of the understanding that most tools and appliances these days are Class II (double insulated) and have no reference to ground, whereby they have a plastic body and no ground conductor.
Yes I can understand that there might be some Class I appliances still out there, but if people are going to use them, would they not use an in-line GFCI/RCD?