Originally Posted by
intuition
True. He didn't buy the ticket, because the agent told him that he would not be able to upgrade as there were 0 availability. Buying the ticket would not have changed the agents attitude towards the problem.
You are right that he could have bought it anyway and called in to get it waitlisted and then call again to cancel it and wait for refund if upgrade didn't clear in 23 hours. That method only works for those who are allowed onto waitlist though.
I don't have a fitting ticket at the moment, but at least 2 months ago I could upgrade the SH segment but not the LH segment. And that was exactly the availability I got per segment in the upgrade availability tool. According to the CS story that should not be possible (anymore). But I would just have tried to do it myself without asking help from CS.