\numberedsection{Enforceability}\label{enforce}

Delayed open source licensing is less explored than immediate open source
licensing, and some observers have expressed concerns about its legal
enforceability. For example, if an author died before the announced license
transition date, would the author's heirs be required to honor the license
transition, or could they potentially cancel or withdraw it? What if a
company were acquired by a new owner which wanted to retroactively change
its licensing structure?

% XXX We obviously don't know yet because ...

The Creative Commons research on springing licenses expressed some concerns
about their enforceability. The Creative Commons organization itself
previously implemented a delayed licensing mechanism called Founders
Copyright; unlike other Creative Commons licenses, the Founders Copyright
involves a copyright assignment to the Creative Commons nonprofit
organization itself. The organization then commits to grant the original
author an exclusive license to the for the announced delay period, and
to license the work to the public afterward. It appears that this copyright
assignment mechanism was intended to minimize uncertainty about the
extent to which authors could bind themselves (or their successors) to
future licensing intentions, although it required direct involvement by
the nonprofit as copyright holder and licensor, a role it had otherwise
not seen fit to take on.

Kyle E. Mitchell distinguishes ``a present grant of a license" (with a
specified future start date) from ``a contractual promise to grant the
license later" and advocates using the former, although he does not
imply that the latter is invalid or unenforceable. Mitchell's concerns
focus on clarity and persistent documentation of specific license
grants to specific code and project versions.