Unable to turn on init process in docker-for-mac

Adding the following docker configuration should add --init to the dockerd daemon and mount tini to /dev/init.

{
  "init" : true
}

No --init flag on the dockerd daemon, no /dev/init mounted into containers

I'm running docker 1.13.1 on macOS 10.12.3, a fresh install of docker for mac

Start docker for mac
Run docker run -it --rm alpine ls /dev, and there is no init entry
Run docker run -it --rm --pid host -e COLUMNS=200 alpine /bin/sh -c "ps aux | grep dockerd", and there is no --init flag added

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