A human on average weighs anywhere from ~110 - ~250 pounds (very broad guess). A human can also fall on and injure a child. And you can be sure that, similar to how bones are covered by layers of tissue and skin, robots designated for household use will be built with materials that improve safety during physical interaction. There isn't much difference.

Also the customer will very likely be asked to sign damage waivers and whatnot as part of the sale/rental agreement.