aros71:hydroksyde:I'd put in an STB and add a logitech harmony remote, then you one remote with a nice "Watch TV" button that will power on the TV and STB, set the input on the TV (assuming it doesn't go out of sync somehow), and then the volume buttons on the remote will control the TV, and the channel buttons will control the STB.
That "assuming it doesn't go out of sync somehow" is the huge flaw in this plan. Cue tech support calls in 3....2.....1....
"My tv is on but the box with the numbers is not showing anything" and "If I press the button the TV goes off and the box with the numbers comes on"...
There will always be additional complexity and points of failure with a two box (screen + STB) model.
You'll just have to take their old TV remote away, and tell them not to touch the buttons on the TV or the world will end...

