Force Push against Arena Wall

[Drealin]

I decided to play Force Push on my wife's vampire, which was in a zone next to the edge of the board.  I wanted to bash it against the Arena Wall.  Would I have to pay 3 mana because of the attack from it being bashed?  Or not because the Arena Walls do not have the Passage Attacks trait, only Passage Blocked and Blocks LoS traits? (page 21 Note)
My wife believes that if her creature would be bashed against the Arena Wall without me having to pay 3 extra mana, then the Force Push card is too powerful for only costing 3 mana to begin with.  Plus it turns an Incantation spell into Attack spell without it actually being an attack, because there are only 2 zones that aren't next to Arena Walls more often your creatures will be next to Arena Walls.

Force Push:
Target creature is Pushed 1 zone in the direction of your choice.  If the target is Pushed through a wall with the Passage Attacks trait, you must pay an additional 3 Mana.
This has no effect on Unmovable creatures.

Push
...The pushed creature suffers any attack from the wall if the wall has the Passage Attacks trait.  If a creature is Pushed into a wall with the Passage Blocked trait, it is bashed against the wall and suffers a 3 die attack.

[Hedge]

the passage attack walls usually do more that three dice damage. that is the reason for the extra mana cost. seems a reasonable cost for its result either way.


Hedge

[paradox22]

I think force push/bash cost is balanced.  It is conditional, so you won't be able to do it all the time due to the enemy position.

Compare it to geyser...Geyser is not conditional, is unavoidable, also does 3 dice of damagr, and has a very good chance to daze...  All for 4 mana, only one more than force push.  Seems very balanced to me.