What does this sticker mean?

Question

i see it all the time. it has a black, then blue, then black stripe again, and its the shape of a square.

Answer 1

In what context do you see this?  Does anyone else see this too?

Answer 2

I found something that says black-blue-black horizontal means "thin blue line" meaning police - the person supports police, has police family member, something along those lines.  I have never seen it myself.