If we could, we would prefer to lock down the Member Status field so that only our small Evangelism admin team could edit it. Unfortunately Arena does not allow this particular field to be locked in this way (most other Arena areas and fields can).
Since Arena is built on top of its own CMS foundation, you have the ability to edit any "screen" (ie page). Fortunately we were able to at least remind everyone what they were told in training by adding an HTML block to that page where the Member Status is updated. For us it now looks like this (see the yellow note box I added):
This is done simply by finding the Edit Family Wizard page and inserting a new HTML control above the existing Family Wizard control as I've done here:
Then back on the Edit Family Wizard page, since I've given myself rights to edit that control, I just update the HTML with the nice WYSIWYG editor and add my fancy yellow text box.
There aren't too many applications that I'm aware of that let you edit them like this.