Actually, upon looking around the wiki a bit more, if you look at the "Talk" page for man_made=survey_point, there is a table with pictures of example tags (uploaded by user T99), and aerial=yes is the first example in that table. This photo gives an idea of what I'm talking about. However, the X in that photo is much smaller than the X markers near Yellowknife - the ones near Yellowknife are around 2-3 meters across.

The tag aerial=yes (now deprecated on the wiki) was originally used for survey points that have a marker visible from the air. In the case of these survey points near Yellowknife, the marker is a giant white X painted on the ground, and the survey marker is at the intersection of the X. This serves the purpose of making it easy to align photographs that have been taken from an airplane with a known point on the ground (accurate to a few centimeters). This is very useful for aligning "Bing Aerial Imagery", or "ESRI World Imagery", and I don't know why it was marked as "deprecated" in the wiki without having replacement tagging.

Based on the wiki, as far as I know, there is currently no way to tag survey points that have markers visible from the air, even though it's a very useful feature for mappers.

Oops. Not sure how I missed that in JOSM validator. I've fixed that, and checked all the other speed limit signs in the area.

Looks like you took away the "construction" status of Stoney Trail motorway and tagged it as an active motorway. I drove past this two days ago and they were still actively paving it. The contractors have not announced it opening. Did you change the status in error? What source do you have for it opening? A major change to a major highway like this should probably go in its own changeset.
Thanks

That import came from the Government of Canada and was quite accurate in my home town, as well as checks throughout the province. I think it may have pre-dated the availability of Bing Maps imagery, using Yahoo aerial imagery at the time, and probably low resolution in Prince Rupert area.
I've looked over your edits, and they look good to me - thanks for letting me know!