Originally posted by: MichaelD
Wow. I'm NOT crazy!
My story is a little different, but very similar.
Ever since I was a child, I could hear a very high-pitched tone coming from almost any TV (CRT) when it was turned ON. After a few seconds, the noise goes away. I have never met anyone else that agreed with me/heard the sound.

Until now.
As the years passed, I read up on basic electronics, etc. It could be a choke of some kind vibrating...maybe even a capacitor charging/discharging.
Any time a CRT monitor is turned on within earshot, I hear that sound. Even from another room. With the advent of LCDs/Plasma etc, i'm hearing it less and less, which is good.
Now, as to your fiancee and her sister. There is a possiblilty that the TV could still make that sound; the capacitors hold a charge when the TV is off/unplugged. Other electronic components could similarly still be energized.
But, I have never heard the sound when the CRT is OFF; plugged in or not.