Be a hostile, belligerent asshole to everyone. If a stranger so much as says "hello" to you, scream at them. Get in their face and accuse them of being scheming fiends.
The good ones with nothing to hide will cower, apologize, flee, and grovel at your feet. The bad ones who hate being opposed will get belligerent in return.
Make it abundantly clear that you are the one in control.