Wow! Another totally useless and unneeded invention.
Whilst this may be clever (and it is, don't get me wrong!) it would be totally unrealistic for them to expect that tv users would actually WANT it.
TV's have enough controls already to limit access to (un)desirable channels, with pin numbers or whatever.
And who is to say that an adult would not want to watch a children's channel? Who is to say that an adult would not ask their child to change to channel 123 because they are currently slicing vegetables and dont want to mess up their remote control or miss their special program?
If they really wanted to progress with this then what would be so wrong with using existing technology - fingerprint scanners are now so compact they are used on some USB memory sticks - why dont they use one of those, and tailor/save any settings made to the user whose fingerprint is currently on the device?