Namely, if someone is using Facebook's AI-powered glasses in my vicinity, I want to get a notification (of some sort) so that I can avoid those persons
Why should the onus be on me to avoid them? I don't want the default to be imagery of myself and family members hoovered up and exploited by an ad company (already made it clear to family that my kids pictures aren't to be shared on any Meta platform). I could even see some reacting violently should they be foisted upon unsuspecting members of the public. It's nothing like CCTV or videos recorded passively on a camera or smartphone which is generally accepted.
Of course they would. They already know who you hate from constant doomscrolling and rage bait. They'll call it asshole avoidance, and charge a premium.
(not affiliated, I did a simple search before writing an app myself)