Pin is just a convenience behavior. The 'Scroll to' behavior simulates 'Every tick - scroll to object.x, object.y', and the Pin behavior simulates placing it at a relative position every tick. The Pin behavior can also still position relatively taking in to account the object scale and angle changing, which involves a bit of trigonometric math, so it's nice it takes care of that for you too.
Recent builds have added more features to pin, like rope or bar style attachment.
As for 2) can you quote where you thought it said this? It's certainly not true, so I don't know why I'd write that in the tutorial :)Ashley2012-06-27 11:03:04