As far as River's concerned, Rose is harmless despite what the girl might think.

"Pity. Though that means I can get away with a lot more than I initially thought." And probably in more elaborate ways than usual if she really wanted. Then again....she would still have to be careful. There was no Doctor here that she trusted to catch her if she were to say... dive off of the 50th floor of a building or something insane like that.