This:

> Use `allow_any_instance_of(Class).to receive` to allow any instance of a class to receive that message

...sounds a bit like a tautology (given that you've just re-stated the code snippet without underscores, periods and parenthesis).

How about this instead:

> Use `allow_any_instance_of(Class).to receive` to configure how instances of a class respond to a particular message without setting an expectation that an instance will receive the message.

Thoughts?