Originally Posted by
SeeBuyFly
Based on the language you used ("J fare", "purchase"), I am assuming that you are NOT talking about an award, but about a paid ticket. Why should people who have bought Y be automatically moved up if J becomes available? That would be crazy--most people buy Y and have no desire to pay for J.
Now with an award, it is possible to take a 'voluntary' downgrade on some segments while paying the full amount of miles for a J award. In those cases, it would be nice if they would fix the issue automatically hen there is availability. But there is nothing in your post that suggests you are talking about awards.
Award travel is no different to paid travel in this respect
with a paid business class ticket, if there is no availability in business class, for the required booking class or if there is no business cabin on a sector, , it is possible to downgrade that sector to economy class
The person has still paid for business class
If availability opens up in the paid for cabin , it is generally quite possible to rebook into the paid for cabin
Some airlines will waitlist the passenger for the higher cabin whilst confirming in the lower cabin and seems a reasonable question on why he has found AA to not do that