Going back to my first post
http://www.scubaboard.com/showpost.php?p=947122&postcount=2
I stated I thought 10% was the right starting place. My comments to Pilot Fish were harsh (my apologies PF) but the comment that $300 was "generous" made me think he thought it was too much. I think it's "right", not generous.
Tipping varies among the cultures on the planet. Tipping in Japan is considered an insult but base wages (and prices) reflect it.
I've done onboard contract work for RCCL so I was privy to the inner workings (and salaries) in the cruise industry. Working in the cruise business is not a bad place to work (at least with RCCL). I would imagine it's not a lot different working on Carnival or Norwegian ship.
Cabin attendents work an average of nine months a year (six on, two off). 20 cabins/attendent X $7 per cabin per day times 270 days PLUS a base salary puts them well over $50k. If they are personable and willing to go "the extra mile", $70k is doable.