@barneygale,
This is for simplifying code and improve readability, since `Readability counts` in The Zen of Python.

Users needn't two lines code to append a file. And there is a minimal modifying to reach it.

If inexperienced users are falling into the hole, just let them in and then learned sth. Because they will go out of the hole sooner or later. 

And finally, two lines cann't prevent them from falling into the hole.