I think the fakery comes in when you are using varied rough black borders to simulate the full frame look. Obviously that is a personal preference and decision, but it does strike me as fakery too.
It's fakery when your INTENT is to say "this is the full frame of my capture with no cropping or editing" by using a simulated film rebate. The look has nothing to do with it, that's just a rendering aesthetic; the intent is a lie if the image framed by the surround is not the full frame recorded on the film.
I used to have a mask overlay that enabled me to add a simulated film rebate when printing 5x7.5 inch prints in the darkroom. You see, I was never concerned with the foolish notion that every photo must be perfectly framed and perfectly captured in its entirety on the film. Given the fact that the VAST majority of reflex viewfinders are far from 100% coverage, and rangefinder/optical tunnel viewfinders are far worse on accuracy than that, the notion of getting exactly what you intend on film right to the corners is more accident than intent. Hogging out my film carriers to capture everything including the rebate, for me, was simply a way to get everything that was captured since the actual image on film does drift a bit from the 24x36mm standard due to focal length: wide lenses create slightly larger negative area, long lenses slightly smaller.
I cut out the borders on my scanner holders the same as I do on my negative carriers. I hate the machine making decisions about how much of my negative I can show, but that is obviously not new with scanning.
Um, photofinishing printers and slide mounts have always introduced an element of variability into what you can get out of a film capture.
The machines are always influencing your content anyway. I shoot loose and work with the standard carrier openings so I can obtain exactly what my intent was through cropping. I can't hog out the negative carriers for my film scanners without destroying them, not to mention that the scanning element is only so large anyway, and that the software driving the scanner limits how many pixels it can retrieve off the film anyway. I can do that with the flatbed scanners, which are lower resolution and nowhere near as precise as the film scanners, or I can scan film using a larger format scanner to capture all the rebate. But these sorts of manipulations are clumsy.
To me, the whole notion of image borders once in the digital space is purely a matter of aesthetics. A simple image border finishes the image rendering. I find hard lines at edges distracting, so I soften the edge with a blurred black surround. For instance:

The border is purely something intended to finish the edges of the image in a pleasing way as this image is no natural film format proportion.
G