My old home is two wire and no ground conductor.
My older LED TV's had three capacitors.
Line to Neutral,Line to Ground Pin and Neutral to Ground Pin.
The current tried to go through the grounded shield on the Cable TV cable.
I had to add a real ground to the cable feed to stop surprises to cable workers.
My later ones are two wire and have a cap between Line and Neutral.
Best not and try to modify the computer supplies.
As the cap helps removing internal noise from the unit back to the power lines and is probably needed for FCC acceptance for the computer.
TED did cause X10 problems as it is constantly send in message on the line and clobbering X10.
I believe the answer was the filter you mentioned to isolate one branch in the home so it could be used with their receiver.
When I was in High School a buddy and I had a business (legal partnership) repairing TV's and Radios.
If you know what a "Tube Caddy" is... it was that far back.
His parents home had a 2 wire, 15 amp service. No grounds. It was all knob and tube inside the walls.
Although the furnace, stove and dryer were all natural gas, the lack of a ground wasn't as big an issue as blowing the one and only fuse in the panel by plugging in too many pieces of test equipment, a soldering iron, etc.
The missing ground was a separate issue. We had to drill a hole in what supposedly passed for "cement" on the basement floor and drive a ground rod into it. Then ran separate ground wires to all the equipment on the benches.
The caps are - I think - what Jeff mentioned. Without an actual ground, the caps to the ground pin would float the chassis at 60v. Wouldn't be deadly as the impedance of the caps would limit the current but you'd still get a good 'buzz' off of touching them.