We tip with the envelopes at the end also. Is it true that these tips "HAVE" to go into a pot for all the ships crew?
From what others have posted on another board I frequent,
If you leave the $10 per day tips on your sign and sail or pre-pay them, any additional cash you give to your room stewards or wait staff, they can keep without question.
If you remove your $10 a day tips, to tip personally, any tips the stewards or waitstaff recieve from you, must be turned in and put into a pool to be split amongst the rest of the crew. (like the $10 a day tips are)
I would guess it is to safeguard that the people who man the buffetts and other venues, don't get completely stiffed.
We would never consider removing any of our $10 a day tips (unless we got the most god awful waiters or stewards) so we just leave them alone and additionally tip anyone else who has given us phenominal service that cruise.
That way, the people we want, get to keep 100% of what we want to tip additionally.