API: should Series.get be strictly label based or allow positional?
The implementation of `Series.get` currenlty simply is:

```python
def get(self, key, default=None):
    try:
        return self[key]
    except (KeyError, ValueError, IndexError):
        return default
```

So it is simply using `[]` / `__getitem__` under the hood.

Somehow I think this is the expected thing, but the consequence is that it brings along all complexities of `__getitem__` in pandas (whether to fallback to positional or not ..). 

So, if we want, we could make `get` more strict by using `loc` under the hood (and it should be possible to do that with a deprecation in a first phase for those cases that `loc` raises but `[]` returns a value).
