Flag to indicate if current image has snapshot.
Sometimes I'll return to an image to work on it and wonder if I snapshot it. So I make a new snapshot, and compare it to latest (and sometimes earlier) snapshots, and delete one if I have a duplicate. It would be great to have Lightroom turn on a flag on the current image after a snapshot to indicate "I have a snapshot of this image" and that flag would turn off the moment you made a new adjustment. If you selected a previous snapshot, or one in history, the flag would also have to reappear. Yes, there could be times when you arrived at settings that duplicated a snapshot perfecly, whether by chance of slider, or other change of adjustments; we wouldn't expect Lightroom to try to figure that out.