I tested this again. If `phinze/cask` is present, we will not get into the `unless` block. We will get this warning and rake will continue to run to completion.

> Warning: Could not tap caskroom/homebrew-cask/brew-cask over phinze/homebrew-cask/brew-cask
> Tapped 1 formula

We will end up having two conflicting taps:

```
$ brew tap
caskroom/cask
phinze/cask
```

But... Running any `brew cask` command will remove the old tap:

```
$ brew cask search
==> Removing legacy Tap
...
$ brew tap
caskroom/cask
```

So we have two good options:

1. Take my original change and remove `phinze/cask` ourselves. That would eliminate the warning and potential confusion for anyone who checks the rake output.
2. Remove L130 and let `brew cask` handle the cleanup itself.

I'm leaning slightly towards 1, but I do understand the concern about having to maintain that line going forward.