Yes - front loading a contract with signing bonuses does in effect reduce the AAV by virtue of the averaging of the years and the time value of money. And by paying the $$ earlier, the player is conferred a benefit that is not reflected in the cap.
Which of the following 5 year cash flows would you want:
Example 1: 12M, $10M, $8M, $5M, and $5M for a total of $40M
or
Example 2: $8M, 8M, 8M, 8M, and 8M for a total of $40M?
Both contracts have the same cap hit of $8M a year. Which deal is better for the player? Obviously Example 1 because of the time value of money. Toronto has used the Example 1 approach on all of their major deals.
On a related note, the first approach also makes it easier to trade the player toward the end of the deal, because the AAV is higher than the actual cash (e.g., Trouba). It makes the player attractive to a team looking to meet the cap minimum.
I hope you're right. Historically the ducks have not played the Toronto game and resisted large signing bonuses. It is probably one of the reasons they could not resign Hampus Lindholm, who got a frontloaded deal from Boston.