What’s the story with the painted WSP sign?

We’ve been on US-29 in Virginia a couple times in the past few months and drove right by Oak Ridge Rd, in fact one time even turned in and checked out the fields to see how they look uninhabited. I always see this concrete block that’s handpainted with “Lockn’ Widespread Panic.” It’s on the southbound side of the highway, but the lettering is seen if you are driving on the northbound side. It’s south of the festival, in Amherst, maybe?, at the entrance to a concrete company. Anyone know the story behind this? If it was right at the entrance to the farm, it would make more sense, but it’s about a half an hour away.