Andrew, I realize this topic is about 6 months old, but I just joined the forum. Anyway, I have detail in my head that might work as a deterrent in the right setting. How about using a piece of corrugated plastic, fiberglass, or metal a couple of inches wide attached to the inside of the beveled portion of the inside of the form for a poured in place seat wall cap. Might be a little difficult to finish but would give you that scalloped edge detail to prevent the grinding. I used to use these corrugated materials to create the old ADA ramps details.
Just an idea, what the heck right that’s why we are here right?