Haven't seen this posted elsewhere in here, but there is an interesting proposal from the useless CTA to recover the cost of dealing with any APPR complaints from the airlines:

Consultation: Air travel complaints fee proposal | Canadian Transportation Agency (otc-cta.gc.ca)

Approximately $790 per complaint. Retroactive, too.

I think it's fair to charge the airlines to be charged a cost recovery (or more) penalty for complaints where they were found to be in the wrong to act as a deterrent, but hopefully complaints would be dropped by a more efficient CTA if they were found to be "vexatious or made in bad faith"