Someone had done this in my town in 07 to about 42 stop signs which cost about 46,000 $ for the city to replace. The writing looks almost exact. I didn't feel it to be an effective slogan at the cost of community funds.
All around Seattle we have signs that say "Stop for me it's the LAW" with a person in the standard walking pose. What someone decided to do was spray paint a C in front of law and draw a hilarious little claw on the walking person. Every time I see one I smile. Street sign fun shouldn't be illegal if you can still read the sign; it brings humor and life to a cookie cutter object. Here is one: [link]
maybe that's the only way the authorities will listen. people like you are the reason nothing ever changes and people just go on doing things for their own selfish reasons. if you don't believe something is right you need to stand up and fight back with whatever tools and means you see fit. you really need to read my newest journal entry on my page.