We've never been notified when upgraded. Our 2nd HAL cruise this past January we were upgraded to a Suite. During check in, I gave the lady the cabin number that I booked, she gave us our keys and off we went. I noticed a few minutes later they had the wrong names and that's how we found out. I don't know why she wanted our passports at check in cause she certainly didn't look at them. Another upgrade we found out about on the website and didn't want it but could not get the cabin we booked back because they had already moved someone there. We were upgraded from a mini-suite to a suite but bad location. We politely complained and were compensated for it. Once we were called and asked to move to a bigger cabin and given $ to do so. That was a good upgrade.
Teresa and Larry
#36-Carnival Splendor 9/16/12
7 night Mexican Riviera
#37-Allure of the Seas 11/11/12
7 night Eastern Caribbean