Because the drain plugs appear virtually identical and because they are close together on a Subaru, these mistakes do tend to happen at quick oil change places. This is just one more of the multitude of posts telling about the destruction of someone’s (pick one): engine/transmission/differential/brake hydraulic system as a result of draining the wrong system and overfilling another.
At this point, almost nothing would surprise me regarding mistakes made at quicky lube places.