We have even taken first time cruisers with us to the welcome back partys. Kind of helps get them addicted! The Diamond party is a whole other party.....
The platinum/diamond party only last about an hour. I alway attend them, but they're really nothing special. Oh yeah, if you have the most cruise credits you get a bottle of Brut. I remember getting one with only 13 cruises. On my last cruise I had 43 cruise credits and didn't even come close. The guy that got the bottle of Brut had 210 credits.