I went through this debate with my DH too.. Sadly they are so determined to be right it will take them a couple of mobile phones and digital cameras to learn the very simple fact of - if you don't want it broken, put it up. It doesn't matter what they do and dont understand, it really doesnt. Its dangerous - lock it up. Its expensive and fragile, put it out of reach. Just because they know they shouldnt touch it does not mean they wont - ever.

Plus - it teaches them what they can't touch in a positive manner. You don't have to yell at them for touching it - they cant. You don't have to smack their hand if they damage it - they cant. But they can't reach it so they know they can't have it. Has worked wonders for us.

I don't think they ever grow out of touching things they know they arent allowed to. As they get older its less about willful defiance and more about fully believing that mum and dad don't trust them but they know they wont break it - so.... Discaplining about that is just going to be a never ending cycle of frustration and tears which can be spared by just putting it out of reach in the first place - and accepting that the TV is gonna get dirty and maybe a little bit broken. LOL