There's a similar sign near SH member Rod Claus' house on a nearby residential airport. To get to/from Rod's house, you drive down the taxiway, and of course, have to yield to taxiing aeroplanes.
When I was in Ketchikan, I saw a local garbage truck that said "Satisfaction guaranteed, or double your garbage back." Then, there's the septic pumper truck that is referred to as "the stool bus". I'm a punster, and I cannot lie...

Steve