I have an inking of what you’re getting at now. I want to try modelling it with full ray tracing now (in the absence of a piece of actual frosted glass!), to convince myself if you’re right (I’m not sure one way or the other), but sadly I doubt I’ll get to it any time soon.

I used physical samples of pebbled glass, curved glass, and clear glass. You can get the same effect using curved glass because of how natural light bounces off of the surface of the subject object and onto the glass, but you don't get this pronounced of effect with a flat panel of glass, frosted or not.

It's too exaggerated for, say, a kernel of 32px.