Discuss one parent kidnapping a child to take the child off to a different jurisdiction such as Middle East to London or London to Middle East. Also, kidnapping over older relatives (capacity, guardianship) to take to kinder tax jurisdictions, elderly protection laws. There are international treaties that are relevant, and this brings together the criminal law with matrimonial law and general civil law. It is also the sort of thing that private client litigators should know about in general, even if they call in a specialist about it.