Galen John,
Why is it a rip off? Is AC not entitled to seek actual cash purchasers for those as yet unclaimed seats? Are they not allowed to make some money? Why should they make the seat available to you ahead of someone WILLING TO BUY THE SEAT?

I'm the last person to defend AC on many things, but your argument makes no sense! AC can sell any number of seats to AE to make available to its members based on projected fill rates for those flights. Many here know that it is common for airlines to allocate two seats at a time in advance of the actual flight. As you get closer to departure, if revenue management feels that those seats will not be filled with paying passengers, they may decide to release more seats. Sometimes this happens sooner, sometimes later. In some cases, especially for premium products, you will never get seats ie: SQ F suites or only at a late date ie: LH.