International parental kidnapping does exist, and does happen. In fact, major news networks reported in September 2014 that a Beijing-bound United Airlines flight had to return to Dulles International Airport after law enforcement was made aware that a mother was illegally taking her child out of the country. Fortunately, the father had a decree with language preventing the child from being removed from the United States without his approval and got wind of the travel before it was too late.
With today’s more mobile workforce and population, it is more important than ever to make sure you address these concerns with specific language in any decree or order regarding children. Without having a court-order to rely on, a parent does not have as strong a basis to prevent these international parental kidnappings. And once out of the country, it is very hard to force any return. There are international laws to refer to and attempt to rely upon, but both countries must be signatories, and even then, the process is expensive, long, and the result uncertain. You are better served by making sure language is in the decree or order preventing international travel without consent, and then making sure the proper law enforcement agencies have flagged the child’s passport in case the other parent attempts to flee.