If babysitting incurred expenses such a extensive travel (fare or gas costs) you should be compensated for any out of pocket expenses. Spending the time with your niece is family stuff and if it is not too great a burden then be a good uncle. read more
Now let's explore the ethics of the second scenario - the shooting of an armed robber, but only with the intent to maim or injure. I have already explained the ethical ramifications of this answer partially in the scenario above, but taking it a bit further I would also like to add that it is the motive and the intent which will be the primary deciding point between the act being ethical or not. read more