Mw13, “I’m sorry, but you’re being ridiculous. Telling a parent or teacher what their kid/student is doing is simply not a question of mesira. Ask any Rav or Possek.”
OK, so WE disagree. It is massering and unless you know how to help the child or you know what the situation is, then in all honestly you are not looking to help anyone just to pass on information. In what way does it help to ring the bell and let the parents know what you saw. How can you know that would help or what the outcome of your report will be. And same goes for going to a Rav with the information”. If you were someone close to the family and saw something, you would KNOW whether or not to tell the parents and how to do it. Such as “Is something going on with your son? I saw something that concerned me and thought I would just ask if everything was OK and if there was anything I could do to help.” If they ask what it was you would then say “I’d rather not say. Maybe I can talk directly to your son about it.”
If one was truly concerned and went to see the Shul Rav you can say “I saw something that concerned me. One of the kids in my neighborhood was mechalel shabbos with a computer on his front lawn in the middle of the night. How can I help him and what should I do with this information?”
FYI, it is NEVER your business to go to kid’s school and masser on them, ever. Even if you are “so absolutely sure” you saw what you saw. Stay out of it, it is NOT your business. You will be the one to start the ball rolling or cause the last straw that gets that kid kicked out and on the road to OTD. Everyone that passes through the life of a child has an obligation to that child. And if you know what the outcome is going to be of your meddling then don’t do it. Going to the school will get the kid thrown out and everyone knows it. That is a given, so stay far away. Going to the parents might not be appreciated either. So sometimes or rather most times it is best to just forget what you saw. Consider it your nisayon. Hashem is testing you to see if you will be a mosser and spread loshon horah or if you will mind your own business.
In your interpretation it might not be messirah at its highest level where it involves the authorities and goyim, but none-the-less, if you masser on someone no good will come of it.