Even if Callie manages to hack the parental notification system so that her parents don't find out she was paddled, there should still be a possibility that her parents find out. Have mom on the couch watching TV (like during the grounding) and if she notices Callie moving slower than usual, she can ask Callie what happened. This gives Callie an opportunity to lie - and maybe mom believes her, or maybe she does a bottom check and Callie's lie is found out.