That looks like a sign on US-23 just over the Michigan border on the way to Ann Arbor.

There's a sign on I-40 west of Oklahoma City where the Federal Pen is that says Warning! Hitchhikers may be escaping inmates.

And there's Arizona's famous signs on Highway 77:

First sign: State Prison

Second sign: (about 100 feet further down the road)Do Not Pick Up Hitchikers

Well, no shit, Einstein, but thanks for the public service announcement.

Well now that sounds all too close to home...