I'll very gladly forward that feedback of yours, to have a dedicated safe-frame even in the preview before clicking the "Render Image" button. 
Also, regarding what you wrote in the edit, that is exactly how it's supposed to work. Would you like us to adjust anything when it comes to that? 
Thank you very much. Now we can match the views exactly at any computers. The "safe frame" mystery has been solved (well at least it was a mystery for me)
The first thing I was expecting when I had 'safe frame' on was, to see the safe frame in the preview. Probably it was my own fault for not trying, but I thought I can only see the safe frame when rendering because I had to click 'render.'
Perhaps slightly grey-out is more difficult than complete black bar? Even so, you can just turn off 'safe frame' if you want to see more than what's in the actual view? Bit it's not like you can actually do any model editing in Enscape (that would be......oh my)
Maybe it's just me, but I just didn't find it very intuitive. Now I know how it works at least. Thank you again for your patience and support.
edit:
I think there's a bug with safe frame. Sometimes it doesn't show safe frame when clicking a render while 'safe frame' is on, it just renders an image straight out as if 'safe frame' were off. It usually happens when I try it the first time after Enscape view is open. i really think 'safe frame' should be shown automatically if 'safe frame' button is checked on.