Lowkey identifying each other?

So many communities use little subtle symbols and stickers and such to help identify each other in public.

For instance, those of us in the BDSM/kink community can pretty easily recognize the triskelion (looks kinda like a yin/yang except has three droplet shapes inside the circle instead of two, is also usually black and white) if we see a sticker like that on a laptop. Most normies would have no idea what that means though.

Are there ways we can sort of identify each other in public that is subtle and not very obvious? A hammer and sickle sticker or Soviet/Chinese flag (or really any red flag with gold stars that looks remotely Communist) on our laptop would draw a lot of unwanted attention if we are just trying to chill in a cafe or some shit.

It'd be nice to know occasionally if I had allies in the same room every now and then, shit's lonely.