With the bale on the forks and suspended in the air a foot or two (as in the 3rd picture above) I've had my bulls or cows come over and start rubbing on or pushing the bale from the other side as I cut the netwrap and take it off. Not aggressive, just playing around and being bulls and cows.  But with the bale on the 4 ft long double forks it doesn't go anywhere. As I go around to pull netwrap from the other side I just speak softly and shoo them away. Anyone that doesn't quickly move back just earned a one way ticket on the next trailer going to the sale barn hamburger sale.