I thought I would share this photo to illustrate the way a typical receptacle tester is fooled when false grounds are present. I am glad I have my Sure test in my bag to properly test the receptacles. Turns out about 3/4 of the ones I tested had false grounds.
One time performing an inspection I was getting, open grounds, reverse polarity, false grounds and then my Ideal tester died. Thankfully it was warrantied and I received a new one.