This is a very tragic accident but no one should be ued. If I'd lost a child I don't think I'd be emotionally capable of suing anyone, it must be a long complicated process. Wherever there are railings, bars, walls...in fact anything 'climb-able' small children will attempt to do it, it's up to parents to lead them away by the hand.
I got stuck (for a minute or two) in a playhouse in ToysRUs last year....I wonder whether my sons would have sued the shop if I'd injured myself? - I never had one as a child, I wanted to know what it was like inside. :o) Apologies for making light in a serious thread Lottie!