People who frequently fall into patterns of behavior that others regard as "creepy" tend to be those who do not find this easy.

Could you create a set of instructions that can easily be followed by people with low levels of social fluency, which would allow them to make this judgment with low levels of false positives and false negatives? If so, you'd be doing a big favor both to people who're frequently exposed to "creepy" behavior, and people who frequently engage in that behavior. It would also probably be unique in the world.