It is frowned on literally, I watched several crew memebers stand by the gangway looking at a print out of people who removed tips, and there were a lot of frowns.
you should leave the autotips alone unless there is a serious problem. then if you like tip cash to whomever you like for outstanding service above and beyond.
IF YOU LEAVE THE TIPS ON, then the people you give extra too will get to keep it. otherwise it goes into the pot for everyone.
I believe that by and large the workers deserve more than the standard tip they recieve.
they work incredilby hard and very long hours 7 days a week. and Tips are their main pay.