While good shoes may be a good protection from soemone's loogie, cigarette butt, gum, mucous or other random "deposits", I'm not sure whether a thin, water-slicked leather or rubber sole will protect you from an energized metal plate.
Some shoes also have nails...
Wonder what the voltage & current in the wires under the plate was. Also...if it was raining and she was wearing shoes, wouldn't the shoes also be drenched with water from the usual unavoidable splashing puddles, etc.? Seems to me like that would have provided an excellent conduction path into her body.
This is really tragic. I also remember reading the story (either here or on another electrical forum) of a little dog that walked on an underground splicebox cover and was also killed when the electricity got him.
The poor little animal was spasming and a guy who tried to administer CPR to the dog also felt a shock.