Someone decided to release seats to lower fare categories whether to accomodate itinerary changes (and collect a change fee) or their sales model accomodates it.

I myself have been watching LGA-YYZ only to find minutes after the sale ended (July 8, 2003), the L availabilty on desired flights shot up from L0 to L7.

[This message has been edited by AAlton (edited 07-11-2003).]