If you discover one, the easiest response is to remove it and move on. Sweep it away, clean the area if you like, and continue with your day. Instead of assuming bad intentions, consider the harmless possibilities first. A calm and practical reaction keeps a small mystery from growing into needless stress. Keeping a porch clean, well-lit, and welcoming can also add to a sense of comfort. If a person in the neighborhood genuinely makes you uneasy, reasonable boundaries are enough. Elaborate rituals are not required to protect peace of mind.
In the end, a mysterious tea bag is almost always nothing more than a forgotten or misplaced object. Rather than allowing internet stories to create anxiety, common sense and calm are the better tools. Sometimes the best way to deal with a strange discovery is simply to sweep that tea bag into the compost bin where it belongs and carry on with ordinary life.