Well, how about this viewpoint: Knob and tube is a fine system so long as it hasn't been tampered with and it isn't used for purposes it wasn't designed for. On the one hand, it is overkill: several inches of spacing between positive and negative wires, porcelain insulators, and neatly soldered connections. On the other hand, the wire is usually 14 guage and doesn't include a ground. It provides a perfect system for lighting a house, but I wouldn't use it for appliances that draw a lot of current. Let's not forget that the primary reason knob and tube was abandoned was that it's excessively labor intensive to install.