I don't get it - why point/wave a fake gun at cops?  What is the purpose of it - do they actually think the cops are going to put their guns down and back off and let them escape?  Or is it a method of committing/instigating 'suicide by cop' because they don't want to go to/return to prison?   

Or - {a hypothesis just to pi** off the cop embracers} - perhaps because pellet guns are untraceable as to who bought them, they are an easy plant after a shooting?  8^}

Gotta say, though - quick research shows that this particular pellet gun does look realistic and threatening ... and they are sold at Walmart.  Was this what he shoplifted?