What do you think about the fact that I once stole a portion of cash on a bus from a grandma who had her purse open a little, and then a few minutes later I told her to close her purse so that no one else could steal anything from her.
Wow, did you really do that?
She didn't realize that her purse was open and I kept quiet about it.
It's good that you told her about her purse being open but what you did beforehand defeats the entire purpose of that good act. Stealing is wrong in general, and you could get in big trouble for doing so.
Hey she wasn't using her money anyway so I can do whatever I want.
Assuming she wasn't going to use her money wasn't your call to make. Regardless, stealing is wrong and illegal. You could end up in jail if you get caught and you're making the life of the person you stole from harder.