By opening door I won $250 & $25 OBC on the Caribbean Princess in October. Make sure to check your daily account, because I didn't even know I won until I saw it on our account during the cruise.
Only reason we added the perk was because of after final payment price of the cruise went down, and I called Princess and we got the upgraded perk.
I cashed most of it in the casino, since we already had so many other perks.