Depends on the parents and what they want to instill in their children.
Some parents strongly advocate free choice where as some push their children to simply follow one or the other.
I grew up with semi-religious parents who followed muslim beliefs and when i was about 21 i started to follow Christianity.
Whether or not the particular religion of choice is gonna be interpreted and understood correctly by a child is totally up to the teacher like with anything else.
I've since been to Christian churches that dont focus on what i strive to get from religion and then others that completely give me what i came to understand.
The message that underlies each and every religion should be the main focus of teaching regardless of which path is chosen. "what goes around comes around" "Do not steal" "do not harm others" "honour your parents" etc
The political side of religion is open to them to indulge in when they get to an appropriate age.