There are UN conventions[1][2] on statelessness that do require the bound parties to provide citizenship under very narrow conditions, essentially to avoid a stateless person. IANAL so I don't know if they apply in this type of example.

[1] https://en.wikipedia.org/wiki/Convention_Relating_to_the_Sta... [2] https://en.wikipedia.org/wiki/Convention_on_the_Reduction_of...