I am no legal expert but this does not mean parents cannot check mobile phones of their children. It is not the case even in the west. My little understanding of law is that the ambiguities in one law could be cleared from another law. Children are under parents protection and parents are even encouraged to control what children do and cannot do online even. So by no stretch of imagination this implies that parents cannot check what their children are doing. It would be ridiculous to interpret it that way.
Read, the link of the bill I sent you, instead of expecting me to cut, paste, highlight and then put it on a website and then sending to you so you could understand it. The bill clearly uses the word, "CHILD " so I assume, it is under 18. Also, invasion of privacy is clearly mentioned in the bill., It can be anything a child has, Why can't it be a mobile?