I've actually heard the opposite before.
My wife and I got married in Branson, but we lived in the Chicago suburbs before that and were moving to southern Illinois. A couple of weeks before the wedding, we got a moving truck and hauled our stuff down into our house in southern Illinois. Then she went on to Branson to get things ready for the wedding, while I caught Greyhound back to the Chicago area so I could work for another 1½ weeks, living out of a backpack. After I was done working, I hitchhiked back down to southern Illinois, where my wife met me. We stayed the night at our new house before heading over to Branson together. (Confused yet?)
Anyway, the hitchhiking sign I'd made had the shape of a big thumb sticking up at one end. I drew a "hitchhiking thumb" there, then added an I-57 shield in the rectangle part, and wrote "Getting Married" as the main text.
My wife's sister rode with her out to meet me in southern Illinois. My last ride dropped me off at the nearest Interstate exit, where my wife and her sister were waiting for me. I later heard my sister-in-law describe my hitchhiking sign to someone, and she talked about how I had drawn a "US Route 57 sign" on it.
I didn't correct her.