The Wonder of the Seas "Fast Facts" document states that there are 2,204 crew members onboard. They ALL deserve a tip. If you average $10 per crew member, that's $22,040. If you're not tipping accordingly, you're being cheap and shouldn't cruise.
Don't the people who fix the elevators deserve a tip?
Security staff?
Guest services?
Next Cruise?
Laundry room staff?
Engine room staff?
Entertainment staff?
Bionic bar robots?
Tech support?
Navigation bridge staff?