Up to version Revit 2014, I would say that pinning objects in Revit was somewhat useless. All it did was prevent you from moving the object. You can still select it, delete it, copy it and change the parameters (such as reference, height, etc.). Sure you get a warning that you just deleted a pinned object. But you can easily click this warning away without ever noticing this.
In Revit 2014, there is an option at the bottom of the drawing window that allows you to not be able to select pinned objects. Great. However, we are still counting on the fact that everyone working on your team has this option engaged. Without this selected, your precious pinned objects still have less than a snowball’s chance in hell of making it through a work day.
If not being able to delete pinned objects isn’t that important, then the warning box should at least be a dialogue box that forces you to hit OK or Cancel after you inadvertently deleted something.