I doubt that these are stealth advertisements but apple know that a vast majority of the people who buy their stuff really, REALLY want others to see that they have them. It's some deluded prestige/ status thing that they perceive apple products gives them.
Like the people walking around malls and driving their Tesla with one on? I think those are completely organic. I think for a little while there will be a subset of people who see them as a status symbol and want the attention.
Branded items are commonplace and are nothing more than neutral objects to some people. They may want to share something interesting without the intent to promote a specific item seen in it.