Residents of Redding, California are reporting mysterious letters and numbers drawn in the dust on their automobiles. Some people are suggesting that the codes could be the work of sex traffickers. For example, "2F" could refer to two females and "1F1B" could mean one female and one boy. Police think the markings are weird but there's no evidence of foul play. From KRCR News:
[Redding Police Sergeant Danny Semtak says] there have been no reports of anyone assaulting, kidnapped, hurt, or anything in that nature following the writing on their windows[…]
"I don't think they should be alarmed but they should be aware when they're going into parking lots. Be aware of your surroundings always know who surrounds you and if you do see something suspicious or you see somebody that's suspicious don't hesitate to call us."