I have found that when the customer has kids the best results are when we keep it as simple as possible when using a second zone from a Denon.

We generally use a basic control panel (such as Xantech) in the second zone that allows volume up/down, zone on/off and source selection.

The panel is then combined with an infra red sensor that allows control of the other components.

This way the parents can have full control in the main zone (perhaps using a Pronto or likewise) and then full control upstairs either using a different remote or the same one with the remote setup using a second zone selection page with aliases to all the source controls, avoiding problems with master(zone 1) volume control and amp source switching (Am I making sense?)

This setup stops any kids messing about with the sources on zone 2 ie changing the track or disc on a CD when someone is listening to it on zone 1.

Some may think it is a waste of a control panel when basic commands of sources could easily be implemented but believe me only a couple of months ago when I was demonstrating a multiroom system to a customer their kids kept pressing buttons on the other panels throughout the house resulting in discs and tracks stopping and starting which ended up is a screaming match between parents and kids (probably wish they hadn't bought the system - not a pretty sight!!).