moving screen

This situation seems to happen a fair amount at the 4th and 5th grade levels. A1 is dribbling in the front court and A2 trys to set a pick on B1, but does not remain stationary (i.e. moving screen) Coach goes ballistic, calling for a moving screen violation. If B1 does not make contact with A2, even though his path is impeded, my interpretation is there is nothing (no violation and W/O any contact, no foul). Am I correct??