I would think AC has a better capacity to control where the code was used to. Can it really be used to go to NRT, SYD, LAX, etc. If this is for a tournamount, you'd think they'd be able to limit it to that specific destination at least, to avoid what seems to be happening now.

I personally wouldn't go near it. While the code may be legit, in terms of being used for transportation to the tournament, my guess is its not legit to use elsewhere. AC could easily cancel the tickets of those who are using it to go to far flung destinations for cheap. Or at a minimum, they should probably contact pax who used the code who shouldn't be, asking if they'd prefer to have the difference between the actual ticket cost for the class of service vs. the cost they got with the code billed to their CC's, or have the tickets cancelled. Another possibility: anyone who added their Aeroplan # to reservations booked with this code could have an account audit coming to them soon, or soon after their reservations are used. Definitely not something I'd look forward to.