In the past, regardless of what you might been told before, upgrades were either on or off on each booking. If you said "no upgrade" you would stay in your current cabin. If you were open to upgrade, you could get ANYTHING in any category above where you were. You couldn't specify, "Well, ask me. I'll take some and not others...". That's not how the computer did them.
It would simply move you without your permission if you were open to upgrade, AND likely move someone else into the cabin you were just taken from. Kind of like a cascade effect. And all automatic in the computer. You might have been able to get back into the cabin that you vacated, but it was very iffy and not at all promised to still be available.
As of this week we have new boxes to choose from!
Now we don't have just on/off, but we have these:
Open to any upgrade (this would be like the old time yes)
Do not upgrade (this would be like the old time no)
And, drum roll....the new one...
Upgrade to a higher category type
So for all of you that would have booked an aft-facing BB balcony and wouldn't want to be moved to a Category BA on Caribe or Lido but WOULD take a mini or suite if it were offered to you, here's your box! Tell your agent or Princess to change your booking to the new option.

The downfall of the new policy is that SUPPOSEDLY they have taken away our ability to say 'no upgrade' on anything we book as a guarantee. That might sound odd to you, but I've done this many times for folks booking Category AD Emerald deck minis who absolutely want the Emerald mini and don't want a Dolphin, but the Emeralds are sold out except for a guarantee. Of course that happens infrequently, so it'll be a while before I can put that new policy 100% to the test by trying it a few times.
Cheers!
Suzy