Volibear, Imposing

Q. How does Volibear Imposing work, especially with regards to involuntary movements such as Charm?

When an opponent moves any number of units to a battlefield other than mine, you draw one (ONLY ONE PER MOVEMENT ACTION).

Volibear Imposing says “when an opponent moves to a battlefield other than mine”.

For our understanding of this effect the subject is “the opponent”, not their unit. Therefore if the opponent moves more than one unit with the same action, you still draw one card.

The effect should be something like: “When an opponent moves any numer of units to a battlefild other than Volibear’s, Volibear’s controller draws a card”.