I don't think it's a Swiss thing at all, there are some who have left their kids alone from all countries, personally I think a "kid" should always be looked after but at what age does that kid become a young adult and how long is "leaving them alone" - putting the bins out, popping to get some milk or a night down the pub?
Probably anything involving duct tape is a little OTT in most peoples opinions, including the Swiss.