The Neighborhood Watch sign is supposed to put would-be criminals on notice that they are being observed. I'm not sure it has much effect, so I have tinkered with it to make it more threatening, and shall we say, "eerie"?
I like your idea of making the Neighborhood Watch seem more frightening to the would-be criminals.
Your photo has certainly made the sign seem more menacing.
OK...eeek...now the bad guy looks more threatening, too! By the same token, I'd say a sign that looked like this would definately put out the vibe that the "watch" part was serious!
Scares me. I promise I will never rob you or anyone else...but I am just a big chicken anyway so wouldn't have done it anyway even without seeing your eerie sign.
Your photo has certainly made the sign seem more menacing.