What is the exact point in time when an uncanceled restricted ticket "no longer has value?" I know it's "after departure," but is that measured to the minute of the scheduled departure time? If I call one minute before posted departure and cancel, that's fine, but if I call one minute after, then the ticket has no value (or requires special dispensation to get the value restored)?

I know the answer based on how the rule is written, but what I'm asking for is how is it actually implemented? Is there some sort of fudge factor that, for example, allows front-line agents to accept a cancellation soon after departure without getting special approval?