We are professionals living in a grammar school area; our DCs are adopted and DS is 10 and just starting at a specialist school that is ages 10 through 16, and unaware that the 11+ exists, except that his one or two friends are busy with tutoring, except he doesn't know they are being tutored, just that they are busy. The GS are single sex and both DCs know we'd prefer them to go to mixed schools.
Now DD is nearing the end of Y3 and lots of parents get their children tutored starting in Y4. There is no way on this earth DD would pass the 11+ (she is just about being moved off "extra help" with English and still has it with Maths) but she is already telling me A, B and C are "going to grammar school". So far luckily this has been boys - but what do you tell your DCs if you are NOT doing the 11+ because there is no point (and you don't like the system particularly, also)?
DD already tells me that B knows more than she does and is "really clever" (I suspect B has difficulty in keeping his opinions about himself to himself, TBH!)
To make matters worse, her best female friend is likely to pass easily without tuition (she knew what mean, median and mode were in Y1) and I am expecting a slew of "ooh, it's so hard whether to tutor or not" moans from other parents in the coming months (rather like the "so, what book band is your DC on" in Reception...)