I guess we have been lucky, but after 60+ cruises on multiple lines I don't remember ever having a room steward tell us no to any request. Then again, we don't ask for much. We have had grands overnight with us on both Carnival & NCL and never had issues with it. On our last Carnival cruise we had one grandson bunk with us the whole week. No issues from the steward.
In your case, I don't believe I would have "taken care" of that steward at the end of the cruise!