I was scared at first too until I realized we're talking about people already taking photos for the purpose of posting to Instagram anyway. It's involuntary surveillance while participating in voluntary surveillance.
How many involuntary social media photo and video backgrounds do you think someone living in NYC or SF is identifiable in every day? I would venture to guess, enough to track a lot of their life. The only thing I see stopping anyone from making this site today is the challenges in scraping large quantities of public data from social media sites. Once you have the data, the rest seems like a solved problem.
https://www.datasciencecentral.com/sunglasses-and-face-mask-...
The real problem is things like gait recognition. Most people already cover some or all of their hips, legs, feet, etc.... But it's hard to hide the way that you walk, regardless of what clothing you wear. And even if you can fake it for a short period of time, it's hard to be consistent about how you fake it over a long period of time.
When you can accurately identify the person who is completely covered head to toe, then it becomes a lot harder to hide.
You really cannot expect any privacy outside anywhere, cameras are basically everywhere now, possibly broadcasting the information to the world.