Medical devices have to meet ground fault/isolation requirements such as 60601-1 (link). Particularly galvanic isolation is required on power and data lines to avoid a fault conditions that could electrocute somebody. Do consumer electronics have any such standards that must be met?
I see this is a real issue that kills up to 70 people a year (link) in consumer tech. Based on designs for common devices like cellphones that I have seen there is no particular care taken to ensure that the chassis can't become dangerously energized when charging from something with a 2 prong charger (No Earth GND). Are there cheap methods that provide sufficient protection such as fuses? Galvanic isolation is typically expensive and difficult for large power draws.