Any of the houses i lived in over the past 40yrs have been grounded through the receptacle mounting screws which is kinda hoky imho. Not sure how my current abode is wired but its about 20yrs old so newer than most of my previous homes. Brendo you could just plug into another outlet as a comparison. The only reason i mention any of this is that we all have expectation bias and if things are no done unbeknownst to us we can not be partial. Now your son on the other hand is completely impartial, i wish i had this opportunity to conduct such an experiment. Perhaps i will get a receptacle and see if anyone notices, afterall they are really inexpensive.
The old house i lived in a few years ago had some really hokey wiring, the house was split into two living quarters and new service panels were installed for each unit. The electrician simply ran new wire to the old panel and used wire nuts to connect the old wiring to the appropriate panel for each room. In 7 yrs there i lost 2 receptacles, they simply quit working requiring extension cords to be run.I also had a boat load of grounding noise especially on my phono preamp. This house is silent as a lamp.
