I think the only cutoff is "lower bound of the height a potentially abusive adult would see it at", and retroactively went back and said "okay this height is av

I think the only cutoff is "lower bound of the height a potentially abusive adult would see it at", and retroactively went back and said "okay this height is average for a 10 year old". According to what I find from a quick google, average height for a 10-year-old is about 4.5", with it starting to spike up dramatically at the age of 12-13 (from ~50 to ~60"). Without knowing the actual height they set this for, though, it's impossible to say how many kids they would or would not get with this kind of advertising.