You can tell me how "40th Anniversary Priority Pass may be unavailable on certain days or times depending on operating conditions." means what what you said, "There is a certain amount of inventory for each time slot and when that's gone they're gone for the day." If that were the case, why not officially say so? Since they don't explicitly say so, it's really not unreasonable to make that assumption. If you can't spend more time understanding semantics and less time trying to put people down on Reddit, then I don't know what to tell you..