Yes, you can have your tips removed and no, they won't grill you.
There is a list kept of the people who have "automatically" tipped, so yes, your room steward as well as your servers have a way of knowing who left the auto tip and who removed it, as well.
I am hopeful you will find that the $10 per person per day is well earned and tip accordingly at the end of your cruise. The purser will be more than happy to provide you with envelopes for tipping.
Carnival Elation March 11
Carnival Imagination Sept 07
Carniival Sensation Dec 06
RCI Sovereign of the Seas Sept 06
Carnival Miracle Sept 05
Carnival Glory Sept 04
Carnival Fantasy Jan 04