Re: I have a more pressing problem re. senior IT
I suspect that a lot of the manufacturers haven't even thought about addressing that yet - though, that said, when it comes to other technologies for the elderly, the Japanese are fairly keen to remind us in their press conferences that they spend lots of money on research, so perhaps once they feel smart TV has reached a more stable state, they'll tackle this.
As you say, settings that can be locked down, for example offering access to catch up players, but hiding all the other IP content, media players and so on, would be useful. Even, in some situations, being able to lock out functionality such as switching from the tuner to a different input (or vice versa, in the case of a Sky customer) could solve some of those annoying problems we've doubtless all faced.
And perhaps, it wouldn't be beyond the wit of man to allow for, say, a five second press of the 'Exit' button to reset the TV to those defaults.