Please, DON'T TOUCH

Bombaywalla, I think the point is that this stuff represents a significant investment, and that children will naturally want to explore it because it looks cool. Should we just let them break something, then laugh it off? How does it build a relationship to see a $3000 oops coming and not do anything to avert it? If Portugall did nothing, and something broke, everyone would feel bad - the guests, hwo may not be able to afford to pay for something which they had no idea was so expensive, the owner, who might feel uncomfortable asking for compensation, and taking what could be a multi-$1000 loss.
I do understand your point, though. If a material posession is going to cause such strife, is it worth it? I would not want to own something that I think would reasonably expect to be broken, for exmple, I don't have expensive glasses. If someone served me a sandwich on the deck on a $500 Noritake plate, and it fell off the arm of the chair, and he wanted me to pay for the plate, I'd be really annoyed; not for owning such a plate, but for setting me up for disaster. By the same token, the owner of a very expensive system should take precautions when he sees an event in which it is likely that damage could occur. Parents should also control their children. just like crossing a street. The pedestrian should only cross when safe to do so. But if he screws up, the driver can't run him over