To Tell or Not To Tell

When I had my second child, naturally I employed my eldest daughter to help me keep an eye on the younger. She had no problem playing the role of "Tai Kar Che" (big sister). However, sometimes it gets out of hand. In a way, I've led her to become "Miss Bossy". She constantly breathes down her brother's neck, barking out what he should and should not do. Sometimes I have to remind her that I am the mother around here, and not her. Hahaha. Then there is the habit of reporting everything the brother does. Everyday I hear:

"Mommy, do you know what D did?"
"Mommy, D blah blah blah..."

It's like her brother has become her obsession.
Now, here is my dilemma. I would like to know if the little one is getting into trouble, but I don't want my girl growing up to be a tell-tale. And I don't want the little one to grow up despising the sister.
It's good for me to know some things but I don't need to know everything. So how do I tell her where to draw the line?

Here are some tips on tattling:

• Don't do it because you want to put the other person down and make yourself look good instead (e.g. Mommy, D made a mess in the room. I already cleaned up my mess)
  
• Don't tell me if the problem can be solved among yourselves (e.g. Mommy, D took all the pillows and won't give me one or Mommy, D spilled his drink)
• Don't do it just so you can get the other person in trouble -- revenge purposes (e.g. Mommy, D ate your last chocolate)
  
• Tell me only if he is going to get hurt or in danger (e.g. Mommy, D fell off his bicycle and is bleeding)
  
• Tell me if something is damaged (e.g. Mommy, D sat on the baby gym and broke it)

I guess the underlying principle to know when to tell and when NOT to tell is: Am I helping or hurting? And have I tried to solve the problem?

Okay, don't think I'm a smarty pants and came up with this solution on my own. Just so happen I still have 1 copy of the Joy Berry book on Tattling. If you want it, you can get it at my bookshop whilst it's still available. Only RM10.

Well, it's definitely a lesson I will have to repeat often. My daughter's "reporting" habit is quite deeply ingrained. Hope I am able to teach her to make good judgement when it comes to making the decision on whether to tell or not to tell.