Are you saying that CPS just drops in on school and randomy interrogates kids about their home life? Or are you saying that is where CPS usually questions kids where there is an allegation of abuse? If the situation is the first, that is disgusting and should be complained about.
If it is the latter option, no you do not have to speak to the authorities. IF you are being abused, you need to do something to stop it. iF it is true and you are afraid of what may happen due to stories you have heard, speak to your priest, minister, pastor, or Rabbi. do not have one, go to any church of your choice. [not deliberately omitting an Islamic cleric, just do not know enough about the religion to know how such a revelation would be addressed.]
The above is not intended as legal advice. The response does not constitute the creation of an attorney client relationship as this forum does not provide for a confidential communication.