Just my curiousity, but isn't the reason they replace the knob and tube wiring because of inductive heating?
Doing it right does mean using the tree analogy. But if you have to live with it while the work is done, it is possible to use a GFCI to work with a 3 prong plug as long as the receptacle is labeled "No Equipment Ground". It's safer than just leaving a 3 hole receptacle with an open ground. NEC 210-7(d)(3).
