[grkvlt]

> who should take care of the kids if something happens to both myself and my spouse

I would expect this to be a very rare occurrence. Most likely is an accident that kills one of the parents only, but in most scenarios where both parents are together, they would have the children with them. I guess it's always important to plan for risks, even if they are rare, if the consequences are very bad - 'high threat, low probability' is the military term, I believe?