b) The earlier promotion? You mean the extravelganza thing? Miles promotions work great because business travelers can spend more employer $$ on a more expensive fare that rewards them with bonus miles. It gets to the heart of why FF programs were invented and why they work. (And why they wouldn't be allowed if they weren't so entrenched...)
No, the early promotion which was "$50 of executive class fare"... thanks Air Canada for the 1% discount....
And agree in general that money off a flight isn't a bad thing (and that it allows some form of price discrimination) for 'on edge' buyers. However, in general these promo's feel relatively pointless -- I can't imagine $50 over 3-4 days sways the purchase of decision of more than a couple of hundred people.
However, great deals (e.g., when west jet used to have tremendous seat sales) swayed a huge number of consumers behaviour.
It simply seems to me that there are more creative ways to sway purchase behaviour.