Red Flag Shirts
Honesty is attractive. A red flag shirt is honesty at scale. "I'M THE RED FLAG THEY WARNED YOU ABOUT". "RED FLAGS, GREAT BRANDING." "I'M A RED FLAG BUT THE MATERIAL IS QUALITY". If they still walk over after reading it, that is on them. You were literally wearing the sign.
Red flag tees are for first dates, festival weekends and any night out where you would like to save everyone some time. They are also the gift of choice for the friend whose dating history is a group chat thread with its own lore. Birthday, Galentine's, the day after they get back with the ex: a red flag shirt fits all three. Every design comes as an oversized organic cotton t-shirt and a hoodie, shipped worldwide, so the warning label is available in every time zone.
I'm the red flag
Green flags are lovely. They also do not sell shirts. Ours are red, they are loud, and they look great in the photo your ex will pretend not to have seen.