Error trying to use macOS 10.14 Mojave installer

[bacongravy]

Running macinbox on macOS 10.14 Mojave and pointing it at the Mojave installer app fails:

$ macinbox --installer /Applications/Install\ macOS\ Mojave.app
• Creating image from installer...
  + Checking macOS versions...
  + Creating and attaching a new blank disk image...
  + Installing macOS...
    - installer: 0% done [|                                                                                                              ]
Errno::ENOENT: No such file or directory @ rb_sysopen - /var/folders/zz/zyxvpxvq6csfxvn_n0000000000000/T/create_image_from_installer.erXa7PnW/scratch_mountpoint/private/etc/rc.installer_cleanup

Re-running with debug reveals that the call to installer is failing:

Sep 30 19:35:35  installer[3157] <Info>: mountDiskImageWithURLString: (null)
Sep 30 19:35:35  installer[3157] <Error>: mountDiskImageWithPath is NOT valid, not attempting to mount
Sep 30 19:35:35  installer[3157] <Error>: Couldn't mount the payload dmg ((null)): Error Domain=com.apple.osinstall Code=-34 "An error occurred while loading the installer resources." UserInfo={NSLocalizedDescription=An error occurred while loading the installer resources.}

This same issue has also been observed in AutoDMG #222 and referenced by @tvsutton and @mikeymikey on Twitter.