>If you ask for latest or a specific tag, it will check out the latest tag, or that specific tag

Yes, but this is not the problem the pull request is trying to solve. As I explained in https://github.com/caitp/grunt-bower-release/issues/35, the goal is to support snapshot dependencies, e.g. in my bower.json I can specify:
```
"some-cool-library: "1.0.0-SNAPSHOT"
```
As a developer of a snapshot dependency, I want to be able to overwrite it. However, the default behaviour of ```grunt-bower-release``` will not permit me doing that, instead it will fail, because it won't be able to push the same tag twice. 

Also, the dependency version in the example ```bower.json``` is a strict one, i.e. it doesn't have any approximation, such as ```~``` or ```^```, because we are explicitly asking for a snapshot version.