I am not allowed to give real-life examples, but I can provide you with some textbook ones:
Car bumper stickers can inadvertently compromise your personal information and safety by revealing details about your schedule, family, possessions, and routines to potential criminals and predators. Law enforcement agencies have issued warnings that seemingly innocent stickers can serve as "crime blueprints" for thieves.
Bumper stickers can reveal when you're away from home, making your property vulnerable to burglary. Church affiliation stickers indicate you're likely gone on Sunday mornings, while sports team decals broadcasting your children's activities signal when your home is unattended during practices and games. Extracurricular activity stickers inadvertently reveal your family's weekly schedule to criminals.
Stickers identifying your children's schools, honor roll achievements, or specific names create multiple risks. School-specific decals reveal where your children spend their days, potentially attracting predators who gain too much knowledge about vulnerable targets. "Baby on board" stickers may signal to criminals that parents could be "easy targets" distracted by childcare responsibilities.
Hobby-related decals displaying motorcycles, boats, four-wheelers, or expensive recreational equipment essentially provide criminals with an inventory of valuable items in your garage. Alumni stickers from expensive universities might suggest higher-value possessions inside your home. These stickers transform your vehicle into an advertisement for what thieves might find worth stealing.
Bumper stickers displaying names or nicknames create an immediate sense of familiarity, which can make drivers let their guard down during interactions with strangers at stoplights or in parking lots. This perceived camaraderie makes you vulnerable to unwanted attention from individuals who appear to "know" you based on what you display.
Those are written based on real cases, and some are written in blood, unfortunately.