I definitely like this. Together with your `link :installer` idea, and letting *homebrew‐cask* take care of the warnings, I think it’s a very acceptable solution.

There’s still the issue, like @phinze mentions on [#14](https://github.com/phinze/homebrew-cask/issues/14), of the installation not being contained within the Caskroom, but I think that is fine as long as it’s explicit in the warning.

There’s also no reason why the installation couldn’t be automatically started (even calling `open` would suffice), if the user asks for it. There are already casks that download *.dmg* files with agreements that show an “Are you sure? Y/N” prompt, so “why not”?