Yeah, that's a bad sign. A similar vehicle drove up while I and a buddy were shooting at a trap range. The dude in this mariachimobile pulled in to a bay, went to his rear hatch and came out with a pistol grip shotgun (this was California). Which was evidently loaded because he started shooting the trap house with buckshot. We were thinking WTF? and getting ready to head for cover. Then the RSO came out yelling STOP STOP! The guy got back in his vehicle and left. RSO called the plates in, but who knows if that amounted to anything.